Just one day after hunting season opened, Sawyer County sheriff's deputies in Exeland said a hunting party returning to one of their elevated tree stands found a man occupying it midday Sunday.

WCCO-TV, Minneapolis, said the group asked him to leave, and he did, but then came back with an assault rifle and started shooting. A victim used a walkie-talkie to call other hunters for help. When they arrived, they were also shot.

"This is completely nuts," Chief Deputy Tim Zeigle of the Sawyer County Sheriff's Department told CNN.

The suspect apparently got lost in the woods after the rampage, and was led out by a pair of hunters who were not aware of the shootings, Zeigle said. His assault rifle was out of ammunition at the time of his arrest.

The three who survived the attack were in critical, serious and fair condition.