FARGO, N.D. (AP) _ A North Dakota State University freshman from Sartell who was killed five years ago died of asphyxia.

Authorities have said little about the September 2014 death of 18-year-old Thomas Bearson, other than it was a homicide.

KVLY-TV obtained Bearson's death certificate, which says he died of asphyxia _ meaning he was deprived of oxygen.

Besides alcohol, two prescription medications were in Bearson's system _ alprazolam, an anti-anxiety drug also known as Xanax, and temazepam, a sedative used to treat insomnia.

Bearson was last seen at a party in Fargo. His body was later found at an RV dealership in Moorhead, Minnesota.

Despite hundreds of tips, no arrests have been made. Moorhead Deputy Police Chief Tory Jacobson says the investigation remains active.