PITTSBURGH -- The fatal Fourth of July shooting of a teenager in Pittsburgh's Hill District remained a mystery on Monday, police said.

Police said they have no suspects and no motive in the murder of 16-year-old Malik Scott.

Scott was shot in the stomach while walking his dog along Adelaide Street at about 11:50 p.m., police said.

Neighbors told police they thought they heard fireworks going off, not gunshots.

"I just heard all the kids scream and I ran up and sat beside him, took his pulse, but he was already gone," said Tasha Leonard.

Leonard was at Robert Williams Memorial Park when Scott was shot. She said he and her son were friends.

"He was quiet, nice, funny, got along with everybody," Leonard said.

Family and friends placed stuffed animals and candles at the park as a memorial for Scott.

"We used to play," said Scott's friend Darius Freeman. "He was a good kid."

Anyone with information is asked to contact police. Police said callers may remain anonymous.