SAN DIEGO

A paraplegic is in critical condition after a sports car he and two youths were in rolled down a grass embankment Saturday afternoon and plunged into Mission Bay.

The unidentified man is in his late teens or early 20s, a UC San Diego Medical Center spokesman said, adding that the man was brought in by a Life Flight helicopter after suffering a head injury.

A 14-year-old girl was behind the wheel of the car when it went into the bay, but she and a 16-year-old passenger were not hurt, San Diego Police Sgt. Micki Farrell said. Their names were not released because of their ages.

Varying accounts were given as to how the car, which had been in a parking lot off Quivera Road, ended up in the bay about 2:20 p.m., Mission Bay Harbor Patrol spokesman Frank Powell said.

“I heard one story that someone . . . was trying to reach for the radio and instead turned the ignition key,” Powell said. “But then, the more common story was that someone tried to start the car in first gear and it lurched forward, then rolled down the hill into the bay.”

The car was submerged in six feet of water when police arrived, Farrell said.