A Kittery man was killed Friday while taking a friend’s motorcycle for a spin in Rye, New Hampshire, police said.

Rye police responded at 9:17 a.m. to a report of a motorcycle accident in the vicinity of 850 South Road.

They found witnesses giving CPR to the 25-year-old victim, who was identified as Matthew Dodge, police said. Dodge was unconscious and not breathing. The motorcycle was found off the road.

Rye paramedics transported Dodge to Portsmouth Regional Hospital, where he was pronounced dead.

Dodge was not wearing a helmet and the cause of death was “substantial head injuries,” Rye police Sgt. Bill Blais said.

“He was heading westbound (on South Road),” Blais said. “He went off the road, slid on the shoulder and then came to rest on top of a stone wall.”

The motorcycle was not registered and Dodge is not believed to be its owner, Blais said.

“He was hanging out with some friends and had taken a motorcycle ride and was heading back to the friend’s house,” Blais said. “We believe it was the friend’s motorcycle.”

Blais could not say whether speed or alcohol were factors in the accident. He said the medical examiner is conducting toxicology tests to ascertain whether Dodge was impaired.

Wet roads did not appear to be a factor in the accident, as the road was dry when officers arrived, Blais said.

Dodge lived at 148 Norton Road in Kittery. Kittery police notified Dodge’s family and transported them to the hospital, Blais said. He did not know Dodge’s time of death.