NORTON - An off-duty Brockton police officer was critically injured early Thursday when he lost control of his motorcycle and crashed into a mail box and a rock on John Scott Boulevard.

Michael Dube, 37, of Dean Street in Norton, was taken to Rhode Island Hospital in Providence.

He was listed in critical condition Thursday night, a hospital spokeswoman said.

Dube, who was wearing a helmet, was thrown from his motorcycle in the 1:25 a.m. crash and suffered a head injury, according to police and fire officials.

Rescue workers found him unconscious. The accident was one of two early morning crashes which occurred within about an hour of each other. Both remain under investigation. In the first accident, around 12:10 a.m., a car struck a utility pole on Richardson Avenue near North Worcester Street.

The driver, Eric Titus, 29, of Mansfield, was released after treatment at Rhode Island Hospital, where he was taken complaining of back and head injuries, authorities said.

In the motorcycle accident, Dube was with a friend, who was on another motorcycle behind him, when he veered out of control in the area of 172 John Scott Blvd., near Mack Avenue, according to police. Patrolman David Ruskey, an accident reconstruction expert, is investigating the accident with Sgt. Todd Jackson and Patrolman Jesse Winters.