A City Beach man was last night fighting for life after trying to jump from the roof of a 10-storey building to a nearby tree.
He sustained life-threatening spinal and head injuries in the fall from the apartment complex in Wembley about 5.30am yesterday.
Police believe the 26-year-old had been at a party at a nearby home on Selby Street earlier in the night.
It is believed he left the party with two friends and two British tourists. He climbed on to the roof with a female tourist and a friend, while the other friend and a male tourist waited on the ground below.
Police believe they initially climbed on to the roof of the building, on the corner of Cambridge and Selby streets, to take in the view and watch the sunrise.
It is understood they may have earlier attempted to climb on to the roof of the Selby Street house.
"He has jumped from the roof to the tree in an attempt to scale down the tree," Det-Sgt Carl Casilli said.
"Unfortunately he has missed the tree and landed on the ground."
Police believe the group had been drinking earlier in the night.
The man is in a critical condition at Royal Perth Hospital but the full extent of his injuries is still being assessed.