A Boy I Never Knew (murder mystery for teens)

Libby was barely awake when her mother came into her room with the shattering news that the boy Libby dated the night before had been murdered. The police were trying to figure out who killed Tony, and why. Libby promised to inform Detective Clark of any suspicious incidents -- like the stranger who muttered a threat to Tony shortly before he died. And there was Libby's best friend, Pam, who seemed to know something, but she wouldn't talk. There was also Matt, a new boy at school -- a rough, tough, troublemaker with a softer side that Libby found very attractive. She wanted to believe he didn't have anything to do with Tony's death, but he was giving Libby mixed messages that left her feeling confused and frightened.