CHICAGO (CBS) — He was just 16 years old, and police say he was gunned down over a bicycle.

Jamal Lockett was fatally shot in the South Shore neighborhood on Saturday.

CBS 2’s Roseanne Tellez talked with relatives about a young man they said would do anything for his family.

He was one of seven children. An older sister spoke, Adora Dismukes, on behalf of the family.

“They just did this for nothing, killed my little brother for nothing. Nothing. It’s just pathetic,” she said Sunday.

Adora says Jamal small in stature and not a threat to anyone.

Police say he was gunned down in the 7300 block of South Coles Avenue in the middle of the day Saturday, not far from his home. He was shot once in the chest, after an argument between two groups of young men.

Published reports indicate the two groups were arguing over the possible theft of a bicycle.

“I don’t know what it is because there are so many stories. All we’re trying to do is get to the bottom of it to see why they killed him over something senseless like this,” the victim’s sister said. “It’s just hurts to know we’re not going to see our little brother again.”

Near the crime scene Sunday, detectives questioned residents and scoured the area for clues. Sources tell CBS 2 there were surveillance cameras rolling, and footage has been turned over to police.

Also near the scene, community activist Andrew Holmes passed out flyers asking that anyone with information about the shooting call a tip line. One resident told us people from Jamal’s neighborhood were not welcome on the street.

“These kids need to graduate instead of being buried. They just need to graduate. So I carry this cap and gown to remind parents,” he said.

Police told Lockett’s family they don’t yet have any firm leads in the case.