Sources told KIRO 7's Kevin McCarty that some of the details police were first gathering in the case had changed after witnesses that didn't want to cooperate with police at first were persuaded to give investigators additional information.

It was originally believed that Shirley, 17, got into an argument moments before he was shot and killed. But investigators now say Shirley and several other people got into a brawl, which heated up quickly.

"The fight started, it kind of broke up and then it grew from there, and it looks like that's what led to the shooting," said Mark Fulghum with the Tacoma Police Department.

Friends remembered Shirley at a candlelight vigil in his honor on Sunday. They said he was known for his volunteer work with Peace Out, a group that encourages young people to get involved in charity work.

Shirley's grandmother, Alberta Potts, said her grandson's death should send a message.

"This is terrible; it has to be for someone to die for everybody to come together and it's wrong," she said. "This is not the way it's supposed to be."

Police still don't have a suspect in the case.

CrimeStoppers of Tacoma and Pierce County will soon offer a reward in the hope that someone may come forward anonymously to tell police who pulled the trigger.