A motorcyclist who collided with a sport utility vehicle in Topsham was in critical condition Wednesday night at Central Maine Medical Center in Lewiston with severe head injuries.

Topsham police Sgt. Mark Gilliam said the 62-year-old man is from Durham but his name will not be released until his relatives have been notified. The man was not wearing a helmet, according to police.

The driver of the SUV, a 2002 Chevrolet Trailblazer, was identified as Charles Mountainland, 51, of Topsham. Gilliam said the SUV hit the motorcycle after it turned onto Route 196 from River Road around 7 p.m.

The cause of the crash remains under investigation.