|Born|| ca. 1958|
|Date|| October 8, 1981|
|Target(s)||Patients at the National Mental Hospital|
Petalvo had been an inmate at the asylum for 21 months on charges of trespassing and physical injuries, but since his condition had sufficiently improved he was recommended for release in the month prior to the attack.
On October 8 the 23-year-old armed himself with a foot-long three-bladed knife, dashed into the dining room of a building he shared with 520 others, and began stabbing at patients, who were lining up for lunch. Eventually he handed his weapon to a fellow inmate, was taken into custody, and confined to an isolation ward.