NEW BEDFORD, Mass. (AP) _ The family of a New Bedford cab driver who was shot to death in his vehicle is suing the state Department of Youth Services and the group home the suspect had left.

Prosecutors said the then-18-year-old Alexander Mills and another person had Donald DePina drive to a remote location, and Mills shot him in the head before taking his belongings in November 2015.

The suit alleges the 66-year-old DePina's death was a result of security failures at the Old Colony YMCA, where Mills escaped. A DYS review found that the door had no alarm and workers lost track of him.

Old Colony YMCA's CEO says the agency is aware of the lawsuit. A DYS spokeswoman declined to comment.

Mills' attorney has said his client has ```significant mental health issues.''