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(CNN) -- Australian police are searching for a saltwater crocodile which killed one man and kept two other men trapped up a tree for 22 hours until they could be rescued by helicopter.

The men were attacked by the four-meter (13-foot) crocodile in the Finniss River in the remote Northern Territory after they entered the river to wash their motorbikes.

The attack occurred on Sunday afternoon when the animal dragged 22-year-old Brett Mann under the water as he stood in the river.

His two 19-year-old companions rushed into the water to try and save him but the crocodile began to attack them, forcing them to climb a tree in the middle of the river to escape.

Moments later they saw the crocodile swim past with Mann's remains in its jaws, the Australian Broadcasting Corporation reported Tuesday.

The men said the crocodile continued to stalk them until they were rescued by helicopter after friends alerted authorities they had not returned from their trail-bike riding expedition.

They were treated for shock and hypothermia at Royal Darwin Hospital on Monday afternoon.

The attack occurred about 80 kilometers (50 miles) south west of the Territory's main city, Darwin.

Police said the river was flooded by the effects of a recent cyclone and was "awash" with animals.

The flooding would make it more difficult to find the animal and retrieve the dead man's remains, a police spokesman said.