Pennsylvania's top prisons official says six homicides allegedly committed by parolees over the past two months are horrendous and he's ordering a review of the parolees' supervision history.
Corrections Secretary John Wetzel told The Associated Press on Wednesday his agency must determine if something should have been done differently.
Dozens of parolees are arrested every year for murder.
Five parolees were arrested this month in the six slayings.
One is a convicted murderer who got out of prison in March and is now charged with killing an 8-year-old boy. Another is charged with fatally shooting off-duty Pittsburgh police officer Calvin Hall. Hall was laid to rest Tuesday.
The corrections officers' union says the cases should warrant an outside review, not internal, and that parole decisions are too automatic.
The parole board ultimately decides which inmates get parole.