The Suffolk County Grand Jury today returned indictments charging two Chelsea residents with murder for the fatal shooting of 17-year-old Ronald Palacios in May, District Attorney Daniel F. Conley announced.

The indictments charge ERLIN MEJIA (D.O.B. 8/10/91) and KEVIN SEMIGLIA (D.O.B. 1/14/90) with one count each of first-degree murder for allegedly shooting Polacios on the afternoon of May 4, causing injuries that would claim the young man’s life at Massachusetts General Hospital the following evening.

The indictments additionally charge Mejia and Semiglia with three counts each of assault with a dangerous weapon and one count each of armed assault with intent to murder for allegedly pointing a gun and firing at members of Palacios’ group during confrontations on Essex and Suffolk streets just before Palacios suffered a gunshot wound to the head.

“These charges reflect painstaking work on the street and in the grand jury,” Conley said. “They demonstrate a commitment by Chelsea Police, State troopers, and Suffolk prosecutors not just to making an arrest but to building the strongest possible case against Mr. Palacios’ killers.”

Assistant District Attorney Mark Zanini led the six-month grand jury investigation that culminated in today’s indictments. Chelsea Police responded to the scene on May 4 and, in light of Palacios’ injuries, notified State Police detectives assigned to the Suffolk DA’s office. Those State Police detectives lead all death investigations in Chelsea, Revere, and Winthrop. Katie Connor is the DA’s assigned victim-witness advocate.

Semiglia is currently in custody on unrelated offenses out of Essex County. His arraignment on these charges has not yet been scheduled but is expected later this month.

Mejia’s location is unknown. Those with information on his whereabouts are urged to call the Chelsea Police tip line at 617-466-4880 or the Suffolk State Police Detective Unit at 617-727-8817.