"The Challenge" star Tyler Duckworth was tragically found "up against the door" of his bathroom when he died.

A case report from the Grand Forks Police Department -- obtained by Page Six -- said that's how the 44-year-old's body was found in his North Dakota apartment.

The person reporting also said they had a tough time reaching the former MTV competitor, according to the outlet.

The report described how the downstairs neighbor -- who had complained of water coming through the ceiling from Tyler's overflowing bathtub -- "tried to get the water shut off" and was "not able to confirm" whether Tyler was alive.

As we previously reported, Grand Forks PD told TMZ ... officers found no outward signs of trauma -- including no gunshot or stab wounds -- and preliminary findings show no indication Tyler's death was a homicide.