Authorities are trying to determine how a Grand Forks, North Dakota, garbage truck ended up in the Red River near the town of Robbin, Minnesota.

Grand Forks police say they have no firm suspects.

Two anglers found the truck Saturday morning a half-mile south of Robbin, around 40 miles north of Grand Forks.

City officials say the truck was stolen late Friday or early Saturday from a fenced lot at the Grand Forks sewage plant. The truck was used to haul treated sludge to the dump.

Kittson County Sheriff Kenny Hultgren says there's no reason to believe anybody drowned during the incident, which left the truck's cab submerged. He thinks someone put it in gear and walked away.

The truck cost $77,000 when Grand Forks bought it in 1994. A replacement would cost about $180,000.