ST. LOUIS -- St. Louis police believe a 15-year-old girl who was shot to death outside her home was the intended target of the attack and wasn't killed at random.

Two masked gunmen with assault rifles fired at Toni Stevenson as she sat alone in a car Tuesday night. She was a sophomore at Northwest Academy of Law High School, a city magnet school that focuses on preparing students for careers in law and law enforcement.

Stevenson, who recently got her learner's permit, was attacked outside her home. She had just parked after coming home from a high-school basketball game she had played in, police Lt. John Green told the St. Louis Post-Dispatch. She was pronounced dead at the scene.

Detectives don't believe the shooting was random.

"We think they were looking for a target, and they found it," Green said. He had no theories about a possible motive.

"I kind of find it hard to believe that a 15-year-old girl would be doing something to cause this to happen," he said.

It was the second fatal shooting since December involving a student from Northwest Academy. Damani Aitch was killed last month. Police have not indicated whether there was any potential connection between the killings.

Stevenson was a "very academically bright child," St. Louis Public Schools spokesman Patrick Wallace said. "Very popular, civic-minded."

She played volleyball and soccer in addition to basketball.

Toni lived in a brick home with her 28-year-old brother, said her aunt, Jada Jenkins. Jenkins became the girl's legal guardian after Toni's mother died of cancer in 2015. She said the girl's father died several years ago.

"She was life," Jenkins said through tears. "Nothing could get her down."

Ethel Walker, 65, lives across the street and heard the shooting. She went outside and saw the wounded girl.

"I said, 'Toni, hold on,'" Walker said. "She looked at me like, 'Granny, I can't.' She still had her backpack on her back."