CLEVELAND (AP) — Charges likely will be brought against the person who took a gun to the house where a 3-year-old boy shot his 1-year-old brother in the head and killed him, the Cleveland police chief said.

Chief Calvin Williams said investigators are trying to determine where the gun in Sunday afternoon's shooting came from and how it was left within reach of a child.

Full details about the shooting on the city's east side weren't released, but Williams said at least one adult was home when it happened.

"A 3-year-old cannot be held accountable for a tragedy like this," said Williams. He said someone had to have supplied the weapon or "knew the weapons were there and didn't do anything to safeguard them, so people will be held accountable for this tragedy."

Police say the older child picked up an unattended gun and shot the 1-year-old. The younger boy, identified as Braylon Robinson, was taken to a nearby hospital and later pronounced dead.

"It's a sad day for Cleveland," Williams told reporters outside the home. "This fascination that we have with handguns, not just in this city but in this country, has to stop. This is a senseless loss of life."

Neighbors said the mother lived in the house with at least three small children.

"They were really nice," next-door neighbor Larry Simpson told Cleveland.com. "It's a shame this had to happen."