The death of a Minnesota man whose body was found along the South Platte River in January has been ruled accidental, according to an autopsy by the Office of the Medical Examiner.

29-year-old Adam Gilbertson was reported missing on December 15. He was last seen shortly before 1 a.m. on surveillance footage leaving Syntax Physic Opera on South Broadway, according to family members.

On January 13, volunteers organized a search party near South Bannock Street and West Alameda and eventually located a body in the 500 block of Platte River Drive that had been there for “some time.”

The body was later identified as Gilbertson’s.

According to the autopsy, Gilberston died from the combined effects of “alcohol, hydrocodone, and amphetamine in combination with possible freshwater drowning, with a significant contributing condition of recent cocaine use.”

Originally from Minnesota, Gilbertson went to school in Wyoming, according to family, before moving to Denver about a year ago.