PISCATAWAY - Authorities are trying to determine whether a Piscataway police officer shot himself or was killed by officers during a standoff at his home Sunday.

Middlesex County Prosecutor Bruce Kaplan said yesterday that Piscataway Police Sgt. David Powell, 46, had threatened to kill any officer who approached the home during the standoff which began Sunday afternoon and ended early yesterday.

Kaplan says the incident began after the 22-year veteran of the force refused to report that he violated a restraining order. The prosecutor says Powell claimed he had a hostage inside his home.

Officials say Powell died of a gunshot wound sometime after he stepped out onto the porch and opened fire on his fellow officers with a 9-millimeter submachine gun. Investigators say SWAT team members returned fire.

A robotic device was eventually sent in and officers determined no one else was in the home.

Neighbor Wendy Richards says that Powell was just divorced by his second wife.