The man recalled nothing further until waking several hours later being sexually attacked by Sinaga.
He immediately pushed Sinaga away, who responded by screaming "intruder" and "help", before repeatedly biting the teenager.
The man hit Sinaga several times, escaped from the flat, and then called police, who arrived to a chaotic scene.
Sinaga, who was discovered semi-conscious with serious injuries,
was at first viewed sympathetically, and the teenager was arrested for assault.
But Sinaga's behaviour in hospital began to arouse suspicion. He kept asking officers to have a mobile phone brought to him from his flat.
Police asked him to confirm the pin number before they would hand it over. However Sinaga gave a series of false numbers, then tried to grab the phone after providing the correct one.
The officer became so suspicious that he seized the phone as potential evidence and, when it was checked, a video recording was found of Sinaga raping the arrested teenager.
The sexual predator who waited outside nightclubs