BOSTON -- Guardian Angels are supposed to help keep the streets of Boston safe, but a Boston volunteer crime fighter was dismissed from the Angels because he is a convicted sex offender, according to the Boston Herald.

The group's leader, Curtis Sliwa, called it a clear violation of the organization's guidelines.

A concerned citizen called police after recognizing Erich L. Kennedy, 35, while he was patroling a Roxbury street.

All of the recruits brought in in recent weeks will now undergo background checks, Sliwa said, and anyone with a criminal background will not be allowed to join the group.