Seems like that information would be useful to have:

National statistics show that hundreds of homicides committed by law-enforcement officers between 2007 and 2012 were not recorded in the FBI's Uniform Crime Report, the Wall Street Journal reports.

More than 550 homicides committed by police during that period were missing, the paper reports. The lack of complete data makes it impossible to accurately determine how many people police kill each year.

Demands for more transparency on such killings have been shoved into the spotlight after the August shooting death of 18-year-old Michael Brown by officer Darren Wilson in Ferguson. The Ferguson police department has only recorded one justifiable homicide between 1976 and 2012, according to statistics.

Local police departments are not required to participate in the FBI’s uniform crime reporting program.

Some agencies tend to not report the killings, Bureau of Justice statistician Alexia Cooper told the journal. Nearly 800 agencies reported about 2,400 killings by police, while more than 18,000 other departments did not report any.

Some entities in the reports said they did not view justifiable homicides by law-enforcement officers as something that should be reported. Some agencies did not consider the events to be actual offenses.

In certain cases, if an officer killed someone in a city or town out of its jurisdiction believed that particular town would handle the report, by they had not done so.