Special Report: The garage science behind the stun gun that changed policing

SCOTTSDALE, Arizona (Reuters) - When Rick Smith launched his supercharged stun gun in 1999, his startup had produced two failed products, several years of losses and a load of debt.

(Clockwise L-R) Two X2 tasers and their respective cartridges, two X26 tasers and their respective cartridges, and the probes that pierce clothing and skin, are seen during a demonstration for Reuters at the department's training academy in Rockville, Maryland, U.S. September 7, 2016. Black tasers are used for SWAT teams; yellow tasers for general police street use. REUTERS/Gary Cameron

He had thrown everything into a weapon he believed police would buy. His challenge was two-fold. He needed something strong enough to stop suspects in their tracks and the science to convince police it wouldn’t kill.

In Smith’s view, the science came together just in time to save his company. His pitch to police: The new Taser was more powerful than any other electroshock weapon. And virtually harmless. Smith himself took a half-second shock at a December 1999 demonstration in Los Angeles and “dropped immediately,” according to a log of the event.

“I can state unequivocally that the ADVANCED TASER is a safe, effective means to bring potentially violent confrontations under control quickly and with minimal risk to police officers and suspects,” Smith said in a letter introducing it to police.

The weapon, he told police, had been subjected to testing comparable to what the U.S. Food and Drug Administration requires – in “a very thorough manner with basic animal studies, quantitative analysis, in-depth worst case animal testing, and human effectiveness testing in over 200 volunteers.”

The human testing, he added, “validated our animal results that the ADVANCED TASER does not leave lasting harm.”

Smith had been right about what police wanted. Sales exploded. Taser International was made. Today, officers around the world and on most U.S. police forces holster the weapon, which Taser says is more akin to a baton than a gun.

But his safety assertions were overstated and rested on science that didn’t rise to the FDA rigor he promised, a Reuters examination of company documents, medical literature and court records found. That science began with one pig, five dogs and some willing cops.

Taser’s human subjects were prospective buyers. At sales demonstrations, police officers volunteered – sometimes for a chance at free beer – to be shocked with the weapon. Those shocks were a fraction as long as what a single Taser trigger squeeze delivers in the field. And the jolts came from darts typically taped to feet, thighs, hips and other places far from the heart.

Researchers observed and chronicled the reactions of the volunteers but took no cardiograms or any other physiological measurements from the subjects. Taser’s early animal and human tests didn’t use control groups – subjects who received no shock or a smaller jolt, for example, and could be used as a benchmark. And CEO Smith’s conclusion that Tasers are “unequivocally” safe was unusual: Scientists typically highlight the limits of their research.

“That certainly was not FDA quality,” said Dr Douglas Zipes, an Indiana University School of Medicine cardiac rhythm expert who has studied the effect of electricity on the heart for more than 40 years and has testified against Taser in wrongful death suits.

“It was woefully inadequate and would not have met any scientific standards for testing,” Zipes said in an interview.

Because Tasers sold to police are unregulated, the company has wide latitude to decide what it tells them. As indications of cardiac risk emerged in its own studies, Taser took months or years to disclose details and issue relevant warnings.

A decade after it happened, Smith acknowledged, contrary to his earlier statement, that one of Taser’s early test animals did suffer a potentially lethal heart disruption, according to a deposition reviewed by Reuters. Years later, when a prototype Taser sent a cop’s heart racing at four times its normal rate, the company waited 18 months for the episode to come to light.

Two decades on, a million Tasers have been deployed around the world. The company says its weapon, used more than pepper spray or the baton, has been fully vetted.

“Taser weapons are the most thoroughly studied and safest force option available to law enforcement,” spokesman Steve Tuttle said in an email. In the company’s view, there are no “confirmed” cases of Taser-induced cardiac arrest, or electrocution, he said.

“There is a small theoretical risk with a perfect probe landing in a very slender person and TASER warns of this,” Tuttle said. “That risk has been estimated at about 1 in 2 or 3 million uses.”

The Taser that raced the cop’s heart was redesigned before release, and that case and all other relevant research was appropriately disclosed, the company said.

Last month, Reuters reported that over a 15-year period, U.S. coroners and medical examiners have cited Tasers as a cause or contributing factor in more than 150 deaths – the very outcome police seek to avoid when they draw the electric weapon instead of their firearm.

There is no consensus on the lethality of Tasers. The risk of cardiac arrest is believed to be low, particularly when the weapons are aimed away from the heart and a standard, 5-second shock is discharged.

But even after hundreds of studies, an independent panel of experts convened by the Council of Canadian Academies and the Canadian Academy of Health Sciences concluded in 2013 there was not enough quality evidence to determine the weapons’ true risk.

One reason for the uncertainty: There are ethical barriers to conducting large human trials, the gold standard of medical evidence, that would mimic real-world police encounters, including chest shots and prolonged or repeated shocks. Another complication: Deaths following Taser shocks often involve other risk factors, such as intoxication and underlying cardiac disease.

What’s more, there is no uniform, publicly available registry of Taser deployments or any other police use of force. The Canadian panel recommended creating one. Tuttle said Taser supports the idea.

There is no doubt the Taser is less a mortal threat than a police service revolver, said James Brophy, a member of the Canadian expert panel, a cardiologist and McGill University Health Centre professor of epidemiology and biostatistics.

The question, he said, is by how much.

“Let’s gather this data, so we can have some kind of meaningful estimate of what the risk is,” Brophy said in an interview.

Behind the debate over the science is the tale of how the company got its transformative weapon to market and dominated the industry even as reports emerged of a risk of cardiac arrest from chest shocks.

Smith declined interview requests. His comments come from Taser records, published interviews, videotaped presentations, articles he wrote and 23 depositions he gave from 2005 through 2012. In April, Taser changed its name to Axon Enterprise Inc to reflect its new emphasis on police cameras and digital evidence management.

In a panel discussion at Stanford University in April, Smith summed up the goal that drives him. “By the end of my life I want to look back and see that bullets are obsolete,” he said. “I view the idea of killing as a technology limitation.”


Taser’s march to market began in 1993 with, as Smith put it, “an entrepreneur with a garage and a good idea.”

The garage and the intellectual property belonged to Jack Cover, a retired NASA Apollo scientist who had invented an early stun gun.

Smith brought drive. A high school valedictorian and football captain, Smith earned a bachelor’s in biology at Harvard University, graduating with honors in three years. He got interested in electrical weapons after two high school football teammates were slain in a shooting blamed on road rage.

The tragedy, Smith said later, made him realize two things. One – gun violence was “a huge problem.” And “two – if somebody could help solve that problem, it could be an enormous business opportunity.”

Smith earned a master’s in business from the University of Chicago and returned home to Scottsdale, Arizona. At 23, the budding entrepreneur called Cover about the scientist’s patented electroshock dart gun, a device inspired by an electrified whale harpoon invented more than a century earlier.

Cover, who died in 2009, invited Smith to visit his museum-like trove of inventions in his Tucson home. Smith left with a deal to commercialize the Taser and his first hire – Cover, a director of science and technology 50 years his senior.

Jack was looking for someone “who would continue his life’s work,” Smith recalled in a deposition. “I was fresh out of school and looking for what to do with my life, and so there was quite a fit there. He became my mentor, at least technologically.”

Dr Robert Stratbucker, Taser’s first medical director, worked with both men.

“Jack had a lot of background in electrical,” Stratbucker said in an interview. “Rick was the one who was short on background. But he didn’t let that get in his way. He is a very smart guy. He picked up on that stuff very quickly.”

Cover told his protégé the commercialization of the Taser in the 1970s had been thwarted by “a very onerous section of the federal codes,” Smith recalled.

Because gunpowder propelled the original Taser’s electrified darts, the device fell under the oversight of the U.S. Bureau of Alcohol, Tobacco and Firearms. Cover wanted to escape the ATF by tweaking the propulsion.

Smith agreed, borrowed his parents’ motor home and moved to Tucson to get started.

Working out of Cover’s garage with parts from a local Ace Hardware store, the pair fashioned a prototype in weeks, swapping out gunpowder for compressed nitrogen.

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They sent it to the ATF. Two weeks later, in November 1993, they got the answer they wanted. The Taser was no longer a firearm – and no longer subject to ATF rules.

“Things moved very fast,” Smith recalled. “In 45 days, we had gone from concept to prototype to approval.”


That was two years after a videotape of a brutal arrest had been beamed around the world. The grainy images showed a man named Rodney King rising from the side of a Los Angeles road even as electrified wires tethered him to a stun gun. The widespread takeaway: Some suspects could fight through painful shocks.

In early 1995, Smith took the Air Taser, his first, to market. Only after the Air Taser failed to knock down police volunteers in demonstrations did Smith conclude the conventional wisdom had been right: The device “was not particularly effective on motivated people,” he recalled in a deposition.

By then, Smith was busy promoting another invention, an electrified steering wheel lock. But the $199 Auto Taser was a “cataclysmic flop,” he said, leaving him with millions of dollars of unsold devices, a miscalculation he later blamed on inadequate research.

Smith returned to the drawing board and his stun gun. With enough power, he figured the weapon would be able to jam the neural system, inducing debilitating muscle contractions.

He hired Stratbucker, an Omaha physician familiar with stun guns. A decade earlier, a sheriff who wore a pacemaker was considering buying a Nova brand first-generation stun device for his deputies. The sheriff asked Stratbucker to vet it.

At the time, Stratbucker tested the Nova 5000 on pigs and dogs, delivering some of the shocks through a catheter into the heart. He attributed the animals’ survival to the duration of the Nova 5000’s electrical pulses, too short to interfere with the heart, he later testified.

In 1996, Smith gave Stratbucker an experimental device and instructed him to find a wave of electricity strong enough to lock up muscles without affecting the heart.

Stratbucker shocked a single anesthetized pig dozens of times, gradually increasing the power until he got the result Smith was looking for. He sent a videotape to Smith.

“We began to see significant muscular activity, so the muscles were reacting, which is what we believed would make for a more effective device in humans,” Smith later said in a deposition.

In his introductory letter to police, Smith pointed to the pig’s survival as evidence of the Taser’s safety.

The pig test was “benign,” Stratbucker later said in a deposition. “We used the same animal over and over and over again. Put him back in the pen.” After a couple of days, he added, “we come back and do him again.”

Relying on a single animal in a safety demonstration is unusual, scientists say. The more subjects in safety studies, the more robust the results.


The team concluded the electrical output was well below the cardiac safety threshold for electrified cattle fences – a proxy standard, since there are none for stun guns.

“We’ve got the answers we need at this point,” Smith recalled saying at the time. “Let’s develop it.”

By then, Smith had maxed out credit cards and tapped friends and family for loans. His father had “mortgaged just about everything,” Smith recalled in a videotaped interview.

“It was in our darkest of days,” he said. “I thought the company was going under.”

Smith hired a moonlighting laptop engineer to design an electronic circuit that would achieve the effect he wanted from eight AA batteries. That done, he retooled an assembly line, and in early 1999, the M26, the model he would bill as the “Advanced Taser,” was put to a human test.

Hans Marrero, a former hand-to-hand combat chief for the U.S. Marine Corps, stepped forward. He was an ideal test candidate, having gone to work for the company as its chief instructor after fighting through the Air Taser’s stun in a demonstration a couple years earlier.

The M26 took Marrero down in 1.5 seconds. He described the shock in a promotional video as more incapacitating than grenade shrapnel.

Smith mounted a road show in 1999, the start of a winning strategy to overcome scientific naïvete and “electricaphobic” views.

“Our average person, our average street cop, even, for example, may not know the difference between electricity and radiation,” Smith said in a deposition.

“So, when they’d hear we are using electrical discharge to incapacity, they’d worry,” he said. “What we were conveying is that this electrical discharge that’s going through the body is at a level that’s not going to affect the heart.”

In demonstrations from Edmonton to Austin, Taser invited cops to take a hit, most of them for half a second, with darts taped to the skin away from the heart. The volunteers’ responses – falls, groans and exclamations – were recorded in logs. But their hearts were not monitored, and no blood tests or other measurements were taken.

“That bad boy smokes ya!” a Nashville officer exclaimed, a company log noted.

Another log extolled the prowess of Blaine, a Royal Canadian Mounted Police officer able to bench press 405 pounds. The bodybuilder was offered three days paid leave if he could pick up a knife three meters away while being shocked. When the shock hit, Blaine dropped but managed to crawl with one hand outstretched to the knife.

A few months later, in late 1999 in Edmonton, the prize was a case of beer for any officer who could advance five feet. Blaine’s feat stood unmatched.

In December 1999, Taser conducted what Smith called a final “experimental validation of safety.” Five lab dogs were shocked nearly 200 times altogether. According to Smith, none went into ventricular fibrillation, a chaotic heartbeat that can lead to death within minutes. He emphasized the point in bold in his introductory letter to police.

Even under “extreme circumstances,” with needles carrying the Taser’s pulses directly to the dogs’ hearts, researchers “were unable to cause a dangerous cardiac fibrillation,” Smith wrote. “I think it becomes apparent that the chances of a random situation occurring in the real world where the ADVANCED TASER would pose a risk to the heart is miniscule.”

Training materials repeated the account: The Taser “does not interrupt the heartbeat.”

After launching the M26, Taser began R&D on a successor – much of it conducted in a garage. It belonged to Magne Nerheim, the moonlighting laptop designer who, by that time, had been hired as a staff engineer.

A car collector, Nerheim’s six-car garage had air conditioning, 12-foot ceilings and elbow room. A veterinarian could drive in a car loaded with testing equipment and park by the table where test pigs were strapped.

“It was actually the nicest test facility we ever had,” Nerheim said later in a deposition. Still, he said, the garage tests were “not very super-controlled experiments.”

Taser introduced the model developed in Nerheim’s garage – the X26 – in 2003. About a year later, the company was embroiled in controversy. Several people died following police encounters involving Tasers. News articles in the company’s hometown Arizona Republic and The New York Times raised questions about Taser’s safety assertions and about the value of the early research.

Smith fought back, citing the original dog test. On an earnings call on July 20, 2004, he asserted Taser “never observed adverse arrhythmias that would be dangerous, much less cardiac fibrillation” in the dogs.

On the call, Smith also previewed the results of a soon-to-be published study. In it, he said, researchers were able to induce ventricular fibrillation in pigs with the X26, but only by turning up the charge to 20 times its standard output.

That Christmas Eve, 2004, Taser’s fax machine spat out more challenging news: a notice that the U.S. Securities and Exchange Commission was investigating whether “we had lied about the safety of our devices,” Smith recalled in a first-person account published online.

The “gut-wrenching” crisis was existential for Taser, Smith said. He feared a bad outcome could bring the corporate “death sentence” – a ban on government contracting, a major source of Taser’s revenue.

The SEC wouldn’t comment on the investigation. But the probe included a look at the 2003 death of a man shocked three times with a Taser in an Indiana jail, according to redacted records of the investigation released to Reuters under the Freedom of Information Act.

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Smith said he disregarded his lawyers’ advice, walked into the SEC’s offices and gave them “everything they were asking for – a transparency judo kick,” he wrote, without recounting what he said. “The investigation ended, and our business got back on track.”

Taser’s challenges weren’t over.


Between 2006 and 2008, a series of pig studies – including one sponsored by Taser – appeared in medical journals demonstrating that Tasers could disrupt the heart.

The company-sponsored study appeared in the Journal of the American College of Cardiology. It showed that shocks to the chest triggered extra heartbeats, a phenomenon known as capture, as well as the more dangerous ventricular fibrillation, but only when more than a standard jolt was applied. Still, the authors advised avoiding the heart.

In a second study in the same journal, independent scientists, led by a doctor with the Canadian Institute of Health Research, subjected six pigs to 150 discharges. Their hearts appeared immune to shocks outside the chest. But when shot in the chest, the stun captured their hearts 79 percent of the time, suggesting the weapon “may have cardiac risks that require further investigation in humans.”

Cardiac capture is not necessarily dangerous. Pacemakers use the phenomenon to keep hearts beating properly. But a heart captured by a rapidly moving outside source of electricity can lead to potentially lethal fibrillation.

To mimic the stress of a police encounter, a response that makes the heart more vulnerable to capture, the Canadians gave the pigs synthetic adrenalin. Taser later said the technique skewed the results.

Then, doctors in Chicago tested Tasers in a series of studies that included assessments of the longer shocks sometimes used by police on combative suspects. They reported that two 40-second shocks resulted in cardiac capture in six out of six pigs. Two developed ventricular fibrillation and died.

Company officials had been briefed on the results of the Taser-sponsored study months before it was published in August 2006. It would be three years before the company warned police of the risk of capture and advised them to avoid chest shots.

In wrongful death suits, the company argued that it had no duty to warn police about the pig studies – or advise them to avoid shocks near the heart – because animal experiments provide theoretical evidence, not proof, of human hazard. Despite its history of touting pig studies, Taser said the animals were poor proxies for people.


In 2007, the nature of the science changed.

The setting this time was a California prison, not a laboratory. A guard pulled a Taser on a 53-year-old inmate attempting to flee. The darts impaled the prisoner’s right chest, delivering two 5-second shocks.

A week later, the prisoner complained of chest pain. He had a pacemaker, and doctors remotely downloaded its electronic record of his cardiac activity, which indicated he had experienced capture.

“Stored event data revealed two high ventricular rate episodes corresponding to the exact time of the Taser application,” the doctors reported in the Journal of Cardiovascular Electrophysiology. They noted that the pacemaker may have helped conduct the electric jolt to the man’s heart.

The case showed the risk of capture, they said, was real – at least for the prisoner with the pacemaker. Taser says the risk is “theoretical.”

In May 2009, another group of heart specialists writing in a medical journal implicated a Taser in a death – the first such finding in the scientific literature. The case involved a 25-year-old man shocked by police three times for 5 seconds each. He collapsed immediately.

The investigators, including a cardiologist on Taser’s scientific advisory board, identified the signature peaks and valleys of ventricular fibrillation on a cardiac activity readout taken just before the young man died. They ruled out other possible causes, including cardiac disease and drugs.

A couple of months later, Taser’s research yielded more signs that stun guns could affect the heart.

It came during pre-market field tests of a new model, the X3. The tests were conducted for the company by Jeffrey Ho and Donald Dawes, emergency room physicians who are paid medical consultants to Taser.

They tested Tasers on both pigs and people.

To evaluate the X3, volunteers were drawn from police training sessions. They were impaled with darts fired from 10 feet. Each got a Taser as compensation.

An ultrasound technician monitored their hearts. Seven subjects got 10-second shocks without apparent problem. Subject No. 8 was another story.

No. 8 was 23, slightly built and distinguished by one feature – pectus excavatum, a sunken breastbone. His heart was close to the surface.

One dart embedded in his right hip, the second in his sternum less than an inch from his heart. His heart rate, 61 pre-test, shot to 240 when the shock hit.

Ho and Dawes watched. No. 8 did not appear to lose consciousness. But, near the end of the 10-second test, he closed his eyes briefly.

When the electricity stopped, his heart rate fell to 57.

The doctors halted the study and notified Taser. The company reconfigured the X3 and put it back to the test. This time, 42 officers took shocks, including No. 8. Everyone appeared to come through okay. But researchers were only able to get heart rhythm readings on 27 subjects, a sample size too small, they noted, to detect a rare event.

The date stamp on the digital readout of No. 8’s racing heart is July 13, 2009.

At the end of September 2009, the company issued a bulletin, advising police against aiming at the chest – the target inscribed into cops’ muscle memory through firearms instruction and, until then, Taser training.

Taser’s bulletin also introduced the “extremely unlikely” possibility that the weapons could affect the heart. It said “changes in heart rate and rhythm,” as well as fibrillation, had been observed in small pigs. The advisory made no mention that a significant change in the heart rate – capture – also had been observed in a cop, Subject No. 8.

Smith addressed the new bulletin in an October 23, 2009 conference call with U.S. police officials.

“Are chest hits with the Taser dangerous?” he asked rhetorically.

“Definitively no.”

Back in 2004, Smith had given stock analysts a public preview of favorable unpublished study results in response to critical media reports about Taser safety. He treated the No. 8 result differently, opting to wait before disclosing the episode.

“Until that is published in the peer-reviewed literature, it’s considered in review or confidential,” he said in a February 2010 deposition. “It’s not for public release until the study’s released.”


Smith revealed in that same 2010 deposition that there had been more to the company’s original dog study a decade earlier – the one he had cited in his first sales letter to police and again to counter safety concerns in 2004.

The disclosure came in a conference room across town from Taser’s headquarters. The occasion was the case of a Watsonville, California, man catastrophically injured in a 2006 Taser encounter.

Police had shocked Steven Butler with an X26 when he refused to get off a bus. Butler, then 45, was drunk and off his psychiatric medication. His heart fibrillated; his breathing stopped. Paramedics revived him, but almost 20 minutes had passed. He was left permanently disabled, unable to care for himself.

Treating physicians attributed his heart episode to the Taser shock, medical records show. Taser told the court the episode could have been caused by other factors, including a history of drug and alcohol abuse and an electrolyte imbalance, according to a report by Westlaw, the legal research service of Thomson Reuters.

The company also said research had not well established that Tasers could trigger ventricular fibrillation or cardiac arrest.

The February 25, 2010 deposition was the third showdown in two years between Smith and the Pasadena lawyer representing Butler. This time, lawyer John Burton teased out something new.

Burton asked: Did the company ever induce fibrillation in the heart of a test animal with a standard Taser?

“Yes,” Smith replied. A dog had gone into fibrillation in 1999.

“Did you tell anybody?”

“That result was not published,” Smith said. The early dog test involved a 5-second shock from a standard M26 Taser, he said. But it was delivered via a catheter into the heart – too extreme to be relevant to police work, he said.

The case settled before trial, with Taser paying Butler $2.85 million; it denied wrongdoing.

In March 2010, eight months after No. 8’s heart was captured, Taser’s research team submitted to a peer-reviewed journal an article about the field test in which it occurred.

In January 2011 – 18 months after the No. 8 episode – Forensic Science International published the piece, “Human cardiovascular effects of a new generation conducted electrical weapon.” The researchers said the episode raised the possibility Tasers could contribute to fibrillation by capturing the heart.

Co-author Ho, who serves as Taser’s medical director, said in an email that his research team is “the world’s leading group” studying the Taser’s effects on people. “We consider all of our findings to be scientifically significant,” he said.

Asked about No. 8, Tuttle said Taser was forthcoming about the episode. “A full case report was published,” he said, citing the journal article. Taser’s view, he said, is that the risk is limited to people with physiques similar to No. 8’s and impaled in precisely the same way.

Three months after publication, the U.K. government advisory committee on less-than-lethal weapons alerted British police organizations about the episode. The committee warned that – even though the case involved an unreleased prototype – all Taser models, including the widely used X26, should be considered as potent.

Because Taser’s police weapons are virtually unregulated in the United States, there was no such official warning in the company’s biggest market.

In Taser-sponsored risk management presentations, the episode was introduced to some police departments with a slide that noted there had been “one capture case” among humans. The slide said nothing more about Subject No. 8.

In March 2013, more than three years after the capture episode, Taser issued a warning that a shock “near the heart has a low probability of inducing extra heartbeats.”

“In rare circumstances, cardiac capture could lead to cardiac arrest,” the bulletin said, again without mentioning No. 8.

An immediate bulletin to cops explaining, in plain English, what happened to No. 8 would have had more impact than the scientific journal article, said Michael Leonesio, a retired Oakland police officer who ran the department’s Taser program. He has served as an expert witness in wrongful death suits against the company.

“Most cops aren’t going to take the time to go out and read these studies and talk to the researchers,” Leonesio said. “Cops are accepting. All they want to hear is it’s safe.”

Additional reporting by Jason Szep, Peter Eisler and Tim Reid; Editing by Ronnie Greene and Michael Williams