Andrew_SadekWAHPETON, N.D. (AP) – The mother of a North Dakota State College of Science student who was missing for two months before his body was found says she believes her son was murdered.

KFGO-AM reports Tammy Sadek says her son was not suicidal. She is calling on North Dakota Attorney General Wayne Stenhjem to investigate his death.

The body of Andrew Sadek was pulled from the Red River in late June. An autopsy report released Saturday shows Sadek died of a gunshot wound to the head.

The autopsy says it was “undetermined” how the gunshot was inflicted, and the toxicology drug test was negative. The report shows he died May 3.

Police released an arrest warrant for Sadek after he’d been missing several days. Police alleged Sadek sold marijuana twice to a police informant.