NEW YORK -- Fromto to , three trials in seven days all ended with juries not convicting police officers charged with fatally shooting black men.
That has led some to ask why convicting officers is so rare.
"They're not easy cases," said Bowling Green State University Professor Philip Stinson, who has been researching that very question.
His data shows police fatally shoot more than 900 people every year. Since 2005, 82 officers have been charged, but only 29 have been convicted, 15 by a jury.
"Jurors are seemingly very reluctant to second-guess the split-second, life-or-death decision of on-duty police officers in potentially violent street encounters," Stinson said.
More importantly, Stinson says, the law is on the officer's side the moment they enter the courtroom, based on a 1989 U.S. Supreme Court ruling that dictates how juries should deliberate.
Jury instructions state that officers can use deadly force if they believe there's an imminent threat to themselves or others. And use of force "must be judged from the perspective of a reasonable officer on the scene" and not with "20/20 ... hindsight."
Though some officers lose their jobs, the objective is to avoid the court cases altogether.
Ron Hosko, president of the Law Enforcement Legal Defense Fund and a former FBI assistant director, says better de-escalation training is needed.
"Not every occasion in America do we need an aggressive bulldog, or certainly a pit bull. We don't need police officers barking at the end of their chain and snapping and snarling at citizens," Hosko said.
At least 20 police officers are waiting to stand trial across the country in use-of-force cases.