Two Trenton police officers were wounded in a shootout that authorities said also left the suspect dead.
Police Director Ralph Rivera said 30-year police veteran Detective Edgar Rios was undergoing surgery for a gunshot wound to his back.
Rivera said Detective James Letts, a 15-year veteran, was shot in the shoulder and is out of surgery.
The officers were going to make an arrest in a domestic violence case when Mercer County Prosecutor Joseph Bocchini said the suspect opened fire as he exited a home on Hobart Avenue on Thursday.
The prosecutor said more than a half dozen bullets were fired.
The name of the suspect has not been released.