A man wounded by gunfire was found several blocks from where the child was killed around the same time, but officials declined to say whether the shootings were related.
Throngs of people eagerly waited on Thursday for more than 100 Palestinian prisoners who were released from Israel in exchange for hostages held in Gaza.
The teenager, Heath Campbell, was shot in the head, the police said. Another boy, 16, who has not been identified, was shot in the shoulder and was in stable condition.