Suspect in custody for fatal Jackson Square stabbing

Updated with names.

Ronaldo Cepeda, 16, of Dorchester, was arraigned today on charges he stabbed Mason Raymond, 17, to death yesterday at the Jackson Square T station.

Raymond, of Hyde Park, died around 4:30 a.m. today, of a single stab wound to the heart, the Suffolk County District Attorney's office says. It provided this account:

Assistant District Attorney Amy Galatis of the DA’s Homicide Unit told [Roxbury Municipal Court] Judge Paul McManus that Cepeda got off a bus and sat down on a bench outside the MBTA station’s turnstiles at about 3:20 yesterday afternoon. A short time later, Raymond entered through a nearby door.

The two, who knew each other, spoke briefly but the words soon escalated to fisticuffs. They separated for a moment, during which Cepeda allegedly produced a knife but held it behind him so Mason could not see it. When they engaged again, Cepeda stabbed Mason.

Boston Police report arresting Cepeda around 2 a.m. at his home in Dorchester.

Innocent, etc.