SINGAPORE national Lee Say Kah, committed suicide Sunday morning by jumping out of a ninth-floor window in the NagaWorld casino and hotel complex, police said.
"We suspect his suicide was the result of drug abuse," said Ou Pov, police chief of the Tonle Bassac commune, Chamkarmon district, on Monday.
"The whole night he had drank beer and taken drugs which made his head noticeably shake."
A report made by the victim's Vietnamese girlfriend said Lee, 40, had gone drinking with his younger brother and their girlfriends at a bar near Wat Phnom on Saturday night.
He had purchased and taken recreational drugs that night and returned to their room at the Naga hotel around 6:00am, Ou Pov said.
They both took sedatives and Lee jumped from the window at 7:15am while his girlfriend was asleep. She only learnt of her boyfriend's death when Naga security guards woke her, Ou Pov said.
"It is a real suicide. There is no reason to believe [the victim's] girlfriend was involved," he added.
Ou Pov said police are examining four pills found in the victim's room.
Lee and his younger brother had booked into the Naga casino two days prior to the death.
They stayed in separate rooms and both had Vietnamese girlfriends whom they had met years ago and had arranged by telephone to meet in Cambodia, police said.
The body of the victim will be kept at Calmette Hospital until the family arranges transportation, police said.
NagaWorld Resort declined to comment.