BOSTON -- The Massachusetts Bay Transportation Authority Green Line operator who was at the controls of a trolley that rear-ended another trolley, injuring more than 60 people, has been indicted by a Suffolk County grand jury.

Two months after the May 8 collision in the tunnels beneath downtown Boston, a Suffolk County Special grand jury returned an indictment charging Aiden Quinn, of Attleboro, with gross negligence by a person in control of a train, a crime punishable by up to three years in state prison or a fine of up to $5,000.

The investigation included sworn testimony from more than a dozen witnesses, phone records and other documentary evidence establishing that Quinn was typing a text message on his Motorola cellular phone while operating Green Line car No. 3612, Suffolk County District Attorney Daniel F. Conley said. That car was leading an attached car and traveling southwest away from Government Center and toward Park Street station shortly after 7 p.m., Conley said. Prosecutors allege that Quinn failed to observe the track ahead of him for a distance of almost 600 feet while he was typing the text message.

As Quinn was texting, he ran through yellow and red warning lights at about 25 mph within the subway tunnel, Conley said. Quinn’s train then struck the two-car train ahead of him, which was stopped at another red light and had its brake lights on, Conley said.

The collision knocked the stationary cars about 36 feet down the track and caused more than $9 million in damages.

A total of 62 passengers on both trains received medical attention after the crash, with 49 transported by ambulance from the scene.