A Mattapan teen was ordered held without bail today at his arraignment on charges he murdered Treshawn Boyd at Washington and Normandy streets in Grove Hall Saturday night.

Daventy Walker, 18, was arraigned in Dorchester District Court on Thursday - on what would have been Boyd's 20th birthday.

Assistant Suffolk County District Attorney Jennifer Hickman told a courtroom filled with Boyd's family and friends and a large contingent of Boston Police officers that detectives are still looking for "one or more" men for the double shooting that killed Boyd and nearly killed a second man - who was rushed to the hospital after a bullet came within an inch of his heart. Workers and customers at a pizza place and a market on Washington Street dropped to the floor as the gunfire erupted outside.

Walker and the others were spotted on surveillance video running from the scene after Boyd and the second victim fell in a hail of bullets, Hickman said.

Hickman said that Walker has a juvenile record that includes two commitments to a DYS facility for firearms violations.

Hickman said after the arraignment that the motive for the shootings remains under investigation.

Boyd's family and friends took up one entire side of the courtroom. In the back of the other side sat a smaller number of Daventy Walker's relatives. Walker's mother wailed as the proceedings concluded and her son was taken back to jail.

Suffolk County DA Rachael Rollins sat at the prosecutor's table; afterwards, she met with Boyd's family. She said three families have had their lives permanently changed because of Walker's "impulsive and horrible decision" to open fire.