Jihad Watters, a 25-year-old African-American man confined to a wheelchair after an earlier shooting, was killed in a brazen daylight attack on May 20, 2010, in Dorchester. He was on the front porch of a Washington Street home preparing to light a grill for his mother’s birthday when, at about 4:30 p.m., he was struck in the back of the head and later pronounced dead at Boston Medical Center. His mother had spoken with him minutes before the shooting and learned of the death when she called back.

Boston police investigated with a working theory that a single shooter acted with an accomplice driving a scooter who dropped the shooter off for a quick getaway, but the probe has been hampered by uncooperative witnesses. No arrests have been announced and the homicide unit continues to seek tips, including anonymous calls to the crime stoppers hotline. If anyone saw activity near Washington Street that afternoon or has information about a scooter or a drop-off, please come forward.