More than 400 fatal police killings a year are sanctioned by local, state and federal authorities as justified homicides, but the FBI doesn’t specifically track how many times officers are prosecuted for improperly causing a person’s death.
The FBI said Tuesday that it doesn’t keep statistics on specific prosecutions of law enforcement officers because it doesn’t track crimes by profession, though it does track justified homicide rulings.
In 2012, the last year available for full statistics, law enforcement ruled a total of 410 deaths as justified homicides, the FBI said. The annual number has been steady for much of the past few decades, officials said.
The FBI defines justifiable homicide as “the killing of a felon by a law enforcement officer in the line of duty.”
The key word in the definition is “felon,” implying someone who already has been convicted of a crime. That leaves a lot of areas out of the data, including people who have committed crimes but completed their sentences, and civilians at large.
The murky statistical picture emerges as Attorney General Eric H. Holder Jr. and more than 40 FBI agents are descending on Ferguson, Missouri, in the aftermath of the death of Michael Brown, an unarmed robbery suspect shot six times by a police officer.
Police say Mr. Brown charged officers, but his family has decried the shooting as needless. The killing has unleashed more than a week of racial tensions, protests, riots and looting.
Another fatal police shooting occurred Tuesday in nearby St. Louis.
Unlike Ferguson, most police shootings don’t get the high-profile attention of the U.S. Justice Department. They are adjudicated by state and local officials in a process in which discretion and interpretation are often key to the outcome, legal analysts said.
It’s often difficult to tell the difference between an officer acting properly or improperly, said Jens David Ohlin, a professor at Cornell University Law School.
“To decide between a lawful act of self-defense and a case of police brutality might hinge on something as simple as where were the suspect’s arms and in what direction were they moving,” he said.
Investigations into what exactly happened in a shooting depend a lot on the people involved, said Charles Rose, a professor at Stetson University College of Law.
“The closer you get to the ground where the event occurs, the closer or further you get from the truth based on the nature of the police department, their integrity and the nature of which it trains,” he said.
Training, Mr. Rose said, is a critical part of police action and needs to be investigated more closely.
“Cops by and large are like soldiers: They react in the moment in the way they were trained,” he said.