A North Dakota State University student from Minnesota who was killed five years ago died of asphyxia.

Authorities have said little about the September 2014 death of 18-year-old Thomas Bearson of Sartell, other than it was a homicide. Bearson’s death certificate says he died from being 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. Despite hundreds of tips, no arrests have been made. Moorhead Deputy Police Chief Tory Jacobson says the investigation remains active.