On the evening of July 24, 2010, 20-year-old Timothy M Walker was shot on the front porch of his grandmother’s home in the Tower Hill neighborhood of Lawrence, Massachusetts. Walker was with a cousin and a friend when an assailant approached, aimed a shotgun and fired a single shot that struck Walker in the head. The shooter ran back to a waiting vehicle, fired again while fleeing, and Walker was taken to Massachusetts General Hospital in Boston, where he died the next day surrounded by family and friends.

The crime was captured on four nearby business security cameras, but the footage did not clearly show the shooter’s face; witnesses described only a man in a dark baseball cap pulled low. Investigators believed Walker was the intended target but the motive remained unclear for months. A May 2011 television segment that aired portions of the surveillance video produced a tip: a 19-year-old Lowell man, Rafael Martinez, confessed to someone watching the broadcast and that person alerted police. Martinez’s girlfriend later identified him from the news story. He was arrested and charged with murder and weapons offenses and held without bail. Jury selection for his trial began April 8, 2013.