July 5 (Reuters) - As the prosecution winds up its case against George Zimmerman for the killing of Trayvon Martin, the accused murderer has been called a truth-teller by the chief detective on the case and allowed to present his story without cross-examination.
While some experts have credited prosecutors with building the best case possible out of sometimes murky evidence, they generally see the case as falling short of proving second-degree murder beyond a reasonable doubt.
One blunder supports that view: prosecutors failed to stop police investigator Chris Serino from expressing his opinion that Zimmerman was telling the truth in his account of killing Martin in self-defense.
Some lawyers see an acquittal, a deadlocked jury, or a conviction on a lesser charge such as manslaughter as more likely, while cautioning they could not conclude how the six-member, all-female jury might see the evidence.
The prosecution began by quoting Zimmerman's expletive-laden call about Martin to a dispatcher, and the jury could still see Zimmerman as the state has portrayed him: a would-be cop who profiled a young black man as a criminal and then pursued him, vigilanate-style.
The prosecution case was due to end on Friday after nine days, giving the defense the option of presenting its own case.
"Those of us who watch trials look for the big flashy knockout punch that resolves the case one way or another," said Richard Gabriel, president of the litigation and trial consulting firm Decision Analysis. "I'm not sure the prosecutors have done that."
The case was ambiguous from the start. Police in the town of Sanford, Florida, originally concluded there was no crime on Feb. 26, 2012, when Zimmerman, now 29, killed Martin, 17, with a single shot to the chest.
Zimmerman told police Martin looked suspicious and admitted at one point to following him, but Sanford police investigators believed Zimmerman's story of acting in self-defense after getting pummeled in a fight.
That decision, followed by protests calling it a racial injustice, turned the homicide into a case of national interest. Zimmerman, who is white and Hispanic, was not arrested until 45 days after the shooting, when a special prosecutor accused him of second-degree murder.
The jury must decide whether to believe Zimmerman, and because prosecutors failed to object to one question on cross-examination, the jury learned that the lead police detective found Zimmerman's story credible.
Sanford Police Investigator Chris Serino, who interrogated Zimmerman, told the jury he concluded the defendant was either telling the truth or was a pathological liar. That's when lead defense attorney Mark O'Mara asked, "Do you think he was telling the truth?"
Prosecutors should have objected to the question, analysts said, but they remained silent.
"Yes," Serino replied.
They objected the next day, when Judge Debra Nelson ruled witnesses were not supposed to comment on the credibility of other witnesses because it was the jury's job to decide who to believe. She ordered the jury to ignore that exchange, which means it cannot be mentioned in closing arguments and they should not consider it during deliberations, but her ruling also called further attention to what Serino said.
"They (prosecutors) clearly missed the objection, and it was very generous of the judge to allow it to be stricken," said Mark NeJame, a Florida defense lawyer who turned down an offer to represent Zimmerman and recommended the defendant hire O'Mara.
"All sides make errors in a case. You're never going to have a perfectly tried case," NeJame said.
For example, defense attorney Don West began opening arguments with a joke that fell flat. "Knock knock. Who's there? George Zimmerman. George Zimmerman who? Good, you're on the jury," he said. He later apologized.
The nine-day prosecution case at times resembled one in favor of the defendant. Zimmerman was allowed to present his version of events repeatedly and largely uncontested in audio and video statements he gave to police, plus in a television interview given to Sean Hannity of Fox News.
The jury saw multiple photos of his bloody and swollen nose, and cuts to the back of his head, showing that Martin clearly got the best of their fight before Zimmerman pulled out his gun.
Prosecutors had to present some of that evidence to establish the basic facts that a homicide was committed, and some of their witnesses were pliable under cross-examination, lawyers said. They were wise to put on some of the evidence helpful to Zimmerman in their own case rather than leave it to the defense case, when it could be seen in an even more favorable light.
Nonetheless, there were risks, such as when prosecutors called Zimmerman's former college instructor for a class on criminal litigation, U.S. Army Captain Alexis Carter, who was friendly toward Zimmerman in the jury's presence and called him an "A" student.
"That's a significant courtroom drama moment that humanizes the defendant. It's not that he's been humanized by a gang member. He's been humanized by an officer of the U.S. military," said William Shepherd, a Florida-based defense lawyer and partner with the firm Holland & Knight.
While Zimmerman was able to speak to the jury without cross-examination through his recorded statements, the jury also saw in the Fox interview Zimmerman saying he regretted nothing about that night, which he attributed to "God's plan."
Prosecutors also may have scored when its hand-picked medical examiner said Zimmerman's injuries were consistent with one punch that could have decked Zimmerman, contradicting his contention Martin repeatedly slammed his head into the concrete.
"I think they presented the strongest evidence available. I think the evidence is strong enough to convict George Zimmerman," said Daryl Parks, a lawyer helping represent the Martin family.