Police are braced for dozens of fresh victims to come forward after an Indonesian student was unmasked as Britain’s most prolific rapist, responsible for attacks on at least 195 men in Manchester.

Reynhard Sinaga, 36, preyed on young straight men in bars and clubs close to his city centre apartment, spiking their drinks with the party drug GHB before attacking them while they slept and filming the rapes on his mobile phone.

Following four trials – which could only be reported for the first time on Monday– Sinaga was convicted of 159 sex attacks, including 136 rapes on 48 victims. But it is feared the number of victims could run into hundreds, as the vast majority of men he targeted were unaware they had been attacked.

When contacted by police, none of the victims wanted to know the details of what happened to them and two went on to attempt suicide.

Sinaga, who moved to Britain in 2007, operated out of his Manchester flat, which was just yards from many of the city’s popular nightclubs and bars.

Leaving the apartment late at night, he would prey on those who looked drunk or vulnerable. After striking up conversation, he would lure them back to his flat with offers of drinks or the opportunity to charge their phones. Sinaga would then spike their drinks with the class-C party drug GHB. He would rape or sexually assault them, often numerous times, filming the attacks on his phone.