John Cerar, a retired NYPD deputy inspector who headed the department’s Tactics and Firearms Section from 1985 through 1994, said the incident was difficult to fathom.

Four shots fired by NYPD officers at a knife-wielding suspect in Midtown Manhattan this week didn't penetrate his jacket -- which was not bullet resistant.

The officer, 27, was in uniform with a civilian jacket and returning home when he was beaten unconscious and robbed of his gun and valuables around 4:12 a.m. in Westchester Square, sources said.