A Long Island police union official says someone yelled "gun" moments before a Nassau County officer was killed in a friendly fire shooting on Saturday night, the AP reports. And police sources say this person is a retired NYPD officer who resides in the area but had no business being at the scene (sounds familiar).

Geoffrey Breitkopf, a 12-year veteran and member of the elite Bureau of Special Operations, was killed after he arrived on the scene carrying a shotgun, dressed in plainclothes but with his police badge around his neck. Breitkopf was responding to a situation involving a knife-wielding satanist who was shot dead by Nassau cops about ten minutes earlier. Witnesses say Breitkopf was wearing his rifle on a sling around his shoulder, its barrel pointed down. "He doesn’t have his finger on the trigger, obviously, but he has his hand on the rifle to secure it to keep it close to his body," Nassau County PBA president James Carver Breitkopf tells the Times.

Breitkopf reportedly "exchanged pleasantries" with Nassau County officers across the street from the house, then said he was going to look around. MTA officer Glenn Gentile had also just arrived at the scene after hearing the call come in from the train station nearby. According to Carver and other sources, an unidentified retired NYPD cop who was milling around saw Breitkopf and yelled "gun!" The Post reports that one of the MTA cops tried to wrestle the rifle away and Gentile fired the fatal shot. Carver says they were trying to handcuff Breitkopf as he lay dying when "his hysterical partner" ran up and identified him.

"There's a lot of anger with my guys right now about this whole thing," Carver tells the Post. "My guy was dead before he hit the ground. He had no chance." NYPD spokesman Paul Browne says he has no knowledge of a retired city sergeant at the scene.