Mike & Riel Series by Norah McClintock

Vin swears he had nothing to do with the robbery—or the two people who were shot. But Sal saw Vin running from the scene. Even after Vin is arrested, Mike isn't sure who to believe. He's caught between his two friends—and believing one might mean losing the other . . .

Mike is stunned when his friend Sal is stabbed to death near the high school. Even though there were lots of kids nearby, nobody comes forward to explain what happened. When Mike starts asking questions, he finds out Sal was hanging around a girl who recently left a gang. Is the gang responsible for killing Sal? How can Mike discover the truth when no one will talk?