(Adds detail about surveillance cameras in eighth paragraph)
By Sarah McBride
April 19 As investigators searched through
videos and photos for clues that ultimately led them to the
suspects in this week's bombing at the Boston Marathon, their
search likely relied more on old-fashioned police work than
technology, officials who work on such investigations say.
Advances in facial-recognition technology and related fields
have been significant in recent years, but the technology mostly
still isn't good enough to match blurry images or those that
show a face only from an angle, say people familiar with
"They probably just applied a lot of eyeballs to this
problem," says Todd Waits, digital investigation and
intelligence director at Carnegie Mellon University's Software
Engineering Institute and a specialist in forensic video
techniques. "It would be a very manual process at first."
Investigators would have likely started simply by looking at
images of the blast itself and worked backward, looking for any
type of suspicious activity. On Thursday, FBI Special Agent
Richard DesLauriers said that law enforcement had observed
images of a suspect setting down his backpack at the site of the
One suspect Tamerlan Tsarnaev, was killed in a shoot-out
overnight. His brother, Dzhokhar Tsarnaev, was captured in a
Boston suburb Friday evening, police said.
Based on similar investigations, technology likely will take
on an increasingly important role for the next stages,
particularly when it comes to examining the suspects' computers
and mobile phones, forensics experts say.
"We would analyze computers, find evidence of Internet
searches for bombmaking, that kind of thing," said Detective
Andrew Kleinick of the Los Angeles Police Department's computer
crimes unit. "Look for emails to see if they've been
corresponding with anyone who might have radicalized them."
In the future, facial recognition technology is likely to
become increasingly relevant to such investigations, enabling
law enforcement to match imperfect images of people captured by
video or cameras to databases of mug shots or passport photos.
Higher resolutions in newer surveillance cameras should help
too, particularly if they are matched by more storage
capabilities in those cameras, Waits said.
Over the four years from 2006 to 2010 accuracy in
facial-recognition algorithms has improved by a factor of 10,
according to the National Institute of Standards and Technology.
Some of the biggest improvements lie in algorithms that
correct for lighting, pose, and expression, says Brian Martin,
director of biometric research at the Safran Group's
MorphoTrust, an identity-services company that works with
The advent of unmanned drones with high-resolution video
cameras, deployed over high-traffic events, could also give law
enforcement important new tools.
"Once they become more commonplace, you'll be able to
honestly go back in time and say, OK, this vehicle or this
person came from over here, went there, entered this subway
stop," says Chris Westphal, chief executive of software company
Visual Analytics. "You'll be able to replay."
While drones have proven controversial because of privacy
concerns - Charlottesville, Virginia, recently banned their use
- they are likely to prove popular with law enforcement because
of their low costs and efficiency.
Expect them over key sporting events, parades and the like
in around five years, Westphal says.
(Reporting by Sarah McBride in San Francisco; Editing by
Jonathan Weber and Lisa Shumaker)