It happened before 4 a.m. in the unit block of Vicky Court.
Police tell Action News officers arrived to find Dominic Neal lying on the front steps of the home. He had been shot in the head.
The homeowner, identified only as an off-duty corrections officer, told police he and his girlfriend were in the home, and the girlfriend had a domestic violence restraining order against Neal.
The corrections officer said he looked out after 3:30 a.m. and saw Neal, wearing a black hooded sweatshirt with the hood up and his head down, walking up the concrete path to the front door.
As Neal reached the front steps, the corrections officer said he shouted for Neal to stop, but he didn't.
Instead, the officer said, Neal reached for the front door with one hand while holding his waistband with the other.
The officer fired three or four shots through the front storm door, hitting Neal once.
Medics took Neal to the Capital Health Regional Medical Center, Fuld Campus in Trenton, where he was pronounced dead just before 9 a.m.
As of Saturday afternoon no charges had been filed in the case.
The incident remains under investigation by the Mercer County Homicide Task Force.