A 52-year-old Sanford man remains in critical condition after he fell off a moving golf cart and hit his head in what authorities described as a freak accident in Casco on Saturday night.

John MacKay remains at Maine Medical Center in Portland after being flown there by a medical helicopter.

His friend, Gary Belinsky, 59, of Westford, Mass., was released from Cumberland County Jail on $300 bail following his arrest on a charge of operating under the influence.

Investigators with the Cumberland County Sheriff’s Office said the incident was not the result of reckless driving, but Belinsky was charged with operating under the influence because police believe his blood-alcohol content was higher than .08 and the golf cart is considered a motor vehicle under state law.

Belinsky and MacKay had been at a barbecue with their spouses earlier in the evening and had been drinking, said Sgt. Paul Thorpe. They were headed elsewhere on the Point Sebago resort. Belinsky was driving with his wife in the passenger seat. The other couple was sitting in seats on the back of the cart, said Sgt. Paul Thorpe.

MacKay apparently stood up at some point, slipped and fell from the moving cart, hitting his head and suffering a brain injury, said Thorpe, who described it as “a freak accident.”

MacKay’s injuries are described as life-threatening.

Belinsky was released on bail from Cumberland County Jail pending a court date.