Herb Whitten

Herb Whitten was a man spotted close at the scene with a Superman shirt walking his dog. He lived in Andover, MA (32 minutes from Boston). He frequently walked his dog downtown. That night, he received a speeding ticket. Due to it only being a speeding ticket, his car was not searched. 

A year after the murder he commited suicide and no note was ever discovered. Some believe he killed himself over guilt for her murder.