FARGO, N.D. (AP) - Attorneys for the family of a North Dakota college student who was a confidential informant for a drug task force before he was found dead are calling for a federal investigation.

The body of 20-year-old Andrew Sadek was found nearly two years ago near Wahpeton in the Red River, which separates North Dakota from Minnesota. An autopsy concluded that Sadek died of a gunshot wound, though it's unclear how his body ended up in the river.

His relatives says they're frustrated with the investigation, which is now in the hands of the Minnesota Bureau of Criminal Apprehension. Attorney Lance Block says the BCA has virtually cut off communication with Sadek's parents.

Officials with the Minnesota BCA said they would comment later Friday.