Police were searching the house at 823 Emerson where murder suspect Ronald Fuller, 23, has lived on and off with Regina Campbell.
Police arrested Fuller Tuesday on a charge of criminal homicide in the weekend shooting death of 13-year-old Jeremy Farrand of Sharon.
Tina Gregory, Ms. Campbell's mother, said she didn't know Fuller very well. He and her daughter had been dating for only a few months, she said.
Sharon Police Chief Raymond C. Greene said Fuller was someone who was known to police but he would not comment on his past arrests. Police said they did not know anything about Fuller's background other than he is not originally from Farrell.
As police carried a shotgun out of the house, Ms. Gregory gasped a bit, saying neither she nor her daughter would have allowed guns in the house.
"I have no idea why they (the guns) were there," she said. "There's kids in that house."
Belinda Gregory, Ms. Campbell's aunt, watched police from an adjacent street corner. She said she was nervous because her niece was still inside.
Neither woman could think of any reason Fuller would have shot Jeremy.
"He (Fuller) liked to stay on the streets a lot," Belinda Gregory said. "It's hard to say what he could get into on the streets."
Fuller was always pleasant around the family, she said, adding that she never heard him threaten anyone. He laughed most of the time, she said.
"I'm puzzled," she said. "But there's so much going on, it's hard to say what triggers some people."