National Use-of-Force Data Collection
The FBI began collecting this data on January 1, 2019. This is part of the Uniform Crime Reports data system. Submission of data is voluntary by police departments and no individual officers are identified.
National Violent Death Reporting System (Centers for Disease Control and Prevention - CDC)
This data collection includes suicides, homicides, accidental violent deaths, etc. A 2016 study entitled Deaths Due to Use of Lethal Force by Law Enforcement used this dataset to analyze data for 17 states from 2009-2012.
Fatal Force (Washington Post)
Since 2015 the Washington Post has tried to catalog every fatal shooting nationwide by a police officer in the line of duty. For this topic, Fatal Force is much more comprehensive than the FBI data. The data is available for downloading.
Tarnished Brass (USA Today)
Researchers at USA Today compiled a database of 85,000 police officers who were investigated for misconduct in 44 states. Most misconduct allegations involved relatively minor issues. However, over 30,000 police officers have been terminated following these investigations. The Tarnished Brass dataset is searchable.