SEAT PLEASANT, MD -- Lamont Adair Jr. spent Saturday participating in a community anti-violence youth summit summit focused on using basketball to find common ground.

Four days later, the 24-year-old pro prospect, who was preparing to join a development league in China, lay dead about two blocks from the Seat Pleasant Activities Center where he was training.

Adair was the target of the 4 p.m. attack near Grieg Street in Seat Pleasant, according to Prince George's County Police. Authorities have not announced a motive or any arrests.

Adiar's family said he aimed to show leadership through athletics to younger players by playing in the "Hoops4Peace" event, which counts nine-time NBA all-star Kevin Durant as an alumni.

"This is a void in our hearts forever," cried Adair's mother Darlene Rainey Adair outside the family's home Thursday.

Adiar's sister Urania Jackson is begging witnesses to come forward.

"He knew he was going to China and he was trying to spend more time with us, not knowing his time with us was limited," she said. "Are we going to find peace? Or is this going to be another unsolved murder because people don't want to come forward?"

Adair had returned to Prince George's County after playing basketball at Illinois Valley Community College.

He worked in family businesses while continuing to train. Adair was a well known figure on D.C. area basketball courts and was being scouted for possible professional play, his family said.

Adair was the father of a son who is about to turn 1-year-old. His Instagram page features touching photographs of father and son.