Captain Walter Lee Peterson, a guard at Western Penitentiary, was killed by inmate Stanley Hoss in a racially-motivated attack on December 10, 1973.
Hoss, a former death row inmate whose sentence had been commuted to life imprisonment, was convicted of first-degree murder for killing Peterson and received a second life sentence. Hoss was originally sentenced to death for killing Verona Police Officer Joseph Zanella on September 19, 1969.
Stanley Hoss hanged himself in prison on December 6, 1978.
State Killings in the Steel City: The History of the Death Penalty in Pittsburgh 