The New York Times reports on a disturbing trend in U.S. law enforcement: though violent crime rates have declined, the number of police officers murdered in the line of duty has risen dramatically. In 2011, 72 officers were killed, a 25 percent increase over the previous year and a 75 percent increase since 2008. Discounting the Oklahoma City and 9/11 terrorist attacks, the 2011 figure is the highest death toll in nearly 20 years.

In an attempt to determine the cause of this trend, the FBI commissioned a study by John Jay College, which the Forum has obtained. The John Jay researchers examined a subset of the murders and found two common trends: nearly all the perpetrators were either mentally ill or had a history of previous violent offenses (PDF). The Times notes that, in response to the report, the FBI has changed what information it will provide to local police departments. “Starting this year, when police officers stop a car and call its license plate into the FBI’s database, they will be told whether the owner of the vehicle has a violent history.” The John Jay report suggests additional training for dealing with “emotionally disturbed persons” could also increase officer safety.