A star basketball player from Langley High School who was the city's top scorer in 2006-07 was shot to death yesterday inside a shop along Hillsboro Street in Sheraden.

Rob Barnes, 20, was pronounced dead at the scene. Homicide detectives said Mr. Barnes entered the store and an argument began between him and a man inside. Police believe the man pulled out a gun and shot Mr. Barnes through the right side of his torso.

Police said they don't know why the men were arguing.

The shooting happened around 1 p.m. inside the Foot Mobile store, a shop that sells both shoes and mobile telephones, located at 649 Hillsboro and across the street from Langley.

City police asked anyone with information to call the Homicide Squad at 412-323-7161.

A 6-foot-1 guard, Mr. Barnes averaged a league-best 24.9 points per game his senior year at Langley. He also led the city league in scoring the preceding winter.

"It's a shame to see another young life disappear again," said Jason Cupples, who coached Mr. Barnes at Langley. "It's a horrible situation. I hate to see young lives taken away like that."

A large crowd gathered in front of the high school yesterday afternoon, with friends and relatives of Mr. Barnes shrieking and crying when investigators from the Allegheny County medical examiner's office took his body from the store.

"He was a good boy," said his aunt, Liz Lane. "He wasn't in the streets."

She said he had been at her nearby home about 15 minutes before the shooting. He told her he was going to Foot Mobile to buy some white t-shirts.

He was the father of a 3-year-old son.

Mr. Barnes never graduated from Langley, but he had been studying for his GED, said Malcolm Thomas, a "prevention and intervention specialist" at the high school.

He had hoped to play college basketball, and he still played in a league at the West Penn Recreation Center in Polish Hill.