An autopsy of a University of Michigan freshman found dead in his dorm room has identified the cause of death as an accidental drug overdose.

A University of Michigan freshman died last month from an accidental heroin and cocaine overdose, according to newly released details from the autopsy.

Michigan news site MLive reports that 18-year-old UMich freshman Thibault deSaintPhalle was found dead in his dorm room last month after he had gone missing for a weekend. Local medical examiners determined the cause of death to be “heroin and cocaine abuse” and the manner of death “accidental,” according to MLive.

A UMich police spokesperson told MLive last month that the death was not being investigated as a homicide and “There are indications of other activities that may have happened that do not involve other people.”

This was the second student death at the University of Michigan this year, following the murder of a medical student over the summer.