That coincides with the historical and anecdotal evidence reported by TPM earlier this week that police officers seldom are charged for homicides committed in the line of duty, though the new data supplies a firmer factual footing.
Experts had repeatedly said that hard data was difficult to come by. TPM contacted Stinson looking for data on Monday, and he initially said that none was available. But then he called TPM on Wednesday and said he realized that his research team had been compiling the necessary information and he ran the data on Wednesday morning.
The new data for what may be the first time puts a hard number on how rare it is for police officers to be arrested for on-duty homicides. As Stinson put it: “I deal in outliers.”
Stinson and his team collected the data as part of an ongoing study, funded by the National Institute of Justice, that examines police officers who were arrested for committing crimes. They have reviewed news archives and police records “to develop the first national profile of police integrity.”
Of the 6,724 arrests that Stinson and company have examined, 664 involved incidents in which officers allegedly used a firearm. Of those, 71 arrests were for murder or non-negligent homicide. And of those 71, 31 were committed while the officer was on duty, Stinson said.
Most of those 31 on-duty arrests cover incidents in which the police were actually performing their official duties, Stinson said. The handful of others were incidents that happened to occur while the officer was on duty or using police equipment but which were not directly related to their police duties, such as a domestic violence incident.
Law enforcement and legal veterans told TPM earlier this week that a convergence of U.S. law, cultural norms and the fact that officers are frequently justified in shooting an assailant contributed to the exceedingly rare instances of an officer being charged or convicted for on-duty homicides.
"It is really hard to convict a police officer," Laurie Levenson, a former federal prosecutor who is now a law professor at Loyola University in Los Angeles, said. "They get a super presumption of innocence."