Chase Chiozza said his neighbors, a group of five young women in a car with their food, parked right next to their place on Patterson Street at 1:35 a.m. Thursday.
Video shows a masked man holding what's believed to be a gun hop over a fence and run across the parking lot, right to the group. Police say he then demanded their belongings.
The man bashed one of the women in her head with his weapon and knocked her to the ground. Chiozza said he took a couple of purses and a wallet, then bolted before police arrived.
Chiozza said officers knocked on his door, waking him up to get a copy of his security video.
Police haven't made any arrests and it's unclear if the robber is connected to other violence in the area.
"I pulled in here last night pretty late," Chiozza said. "I was looking around making sure, you know, there wasn't anyone out here."