He was a kid embracing life and trying to make something of himself, his mother said, just 15 years old and rapping at parties for money, filming music videos with friends.

But Monday night, rising 10th grader Tyhir Barnes died after he was shot leaving a basketball game he'd watched with friends in Southwest Philadelphia, according to police.

Authorities believe the shooting resulted from a days-old dispute over a hoops contest, with an opponent seeking retribution against Barnes' team for a contentious buzzer-beating win.

"It really doesn't make any sense," said Capt. James Clark of the Homicide Unit. "It was over a basketball game ... and now we have a 15-year-old shot and killed."

Two other teens in Barnes' group - ages 16 and 14 - also were hit by bullets around 10 p.m. Monday on the 6000 block of Baltimore Avenue, police said. Both were in stable condition.

Police did not identify them or the suspected shooter, but Clark said he expected that a teenage assailant would be arrested quickly.

Barnes' mother, Tanisha Pratt-Thomas, 41, said outside her Kingsessing home Tuesday morning that her son - one of six siblings - largely had avoided trouble and "was a really good kid. He was my rock."

"I am so heartbroken," she said, flipping through cellphone photos and videos of her son while occasionally wiping back tears.

Since January, at least 33 juveniles have been struck by gunfire across Philadelphia, and seven have died. In just the past week, seven children have been shot in five incidents in the city.

Despite the apparent surge, however, gunfire involving children has diminished in recent years, according to police statistics. In 2015, for example, there were 93 juvenile shooting victims, down from 121 in 2009 - a 23 percent decrease.

The numbers mirror an overall decrease in shooting victims in recent years: In 2014, there were 1,047 total shooting victims citywide, police statistics say, 31 percent fewer than 2009, when there were 1,521.

Still, Barnes' murder was jarring even to Clark, who called it "senseless" and "tragic."

The captain said it appeared that someone associated with a basketball team from 56th and Christian Streets had fired 10 bullets from a semiautomatic weapon at Barnes and his friends, members of a team from 60th Street and Baltimore Avenue. The squads had fought last week after Barnes' squad won a game at the buzzer, Clark said, and that trash talk may have provoked the shooting.

The 56th Street team on Monday "laid in wait and ambushed" Barnes' group after they watched a game at Cobbs Creek Park, Clark said.

Adult coaches and others were helping Tuesday to narrow the pool of potential suspects, although Clark said police believe the shooter was a teenager.

Pratt-Thomas and her mourning relatives welcomed a steady stream of well-wishers Tuesday morning.

Pratt-Thomas said her son had just finished his freshman year at Boys' Latin of Philadelphia Charter, and was an avid basketball player and rapper. He would shoot hoops with other teens in the neighborhood or record music at a nearby studio, she said. He filmed YouTube videos of original songs under the name Jaquil - his middle name - and performed them at block parties over the summer, according to his mother.

Kim Ardley, who taught Barnes in seventh and eighth grades at Add B. Anderson School, said Tuesday that Barnes was "becoming such a young man," and was often a leader for many in her class. When kids were goofing off before eighth grade graduation, for example, Barnes turned around and told them, " 'Guys, our parents are going to see us tomorrow - we've got to get this right,' " Ardley recalled.

Johanna Lanham, a family friend, called Barnes respectful and family-oriented, describing him as "trouble free" while she choked back tears outside Pratt-Thomas' home.

Lanham shook her head trying to accept that an adolescent dispute could lead to such permanent heartache.

"I was sick to my stomach," she said. "I don't get it. I honestly just don't get it."


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Staff writer Dylan Purcell contributed to this article.