Police in Manchester believe the PhD student dubbed “Britain’s worst ever rapist” may have attacked men as far back as 2005 – and have admitted he called them at least twice to help evict men from his flat.

Reynhard Sinaga, 36, from Indonesia, posed as a “good Samaritan” outside clubs in central Manchester, inviting men back to his flat for a drink or to charge their phones, before slipping the date rape drug gamma-hydroxybutyrate (GHB) into their drink. He then recorded himself raping them, sometimes for hours at a time.

‘I thought, OK, he goes for drunk guys’: friends and flatmates on the Reynhard Sinaga they knew Read more

He was convicted earlier this month of drugging and assaulting 48 men between 1 January 2015 and 2 June 2017. But detectives from Greater Manchester police (GMP) think he may have begun raping men in 2005.

They have found photos, videos and “trophy items” that suggest he attacked 195 men between 2005 and 2017.

One of Sinaga’s former flatmates, between 2013-2015, told the Guardian that he now believes Sinaga may have been raping men while they lived together.

In an exclusive interview with the Guardian’s Weekend magazine, the 27-year-old said he met one potential victim in 2014. He remembers a young man knocked on the door to say he had woken up in the flat and wanted to know if he had been raped.

The flatmate did not report it to the police at the time but now says he will help any victims he met by giving evidence for them in court.

Sinaga had no criminal record and had never been suspected of any crimes until 2 June 2017, when his final victim woke up mid-assault and beat him up so badly that he was taken to hospital.

In an account confirmed by GMP, the flatmate also remembered Sinaga twice calling 999 – once when a man he brought home turned violent, and oncein February 2015, to ask for help evicting said flatmate.

In the first instance, the flatmate recalled Sinaga bringing home a “giant, terrifying-looking man” who ended up starting a fight shortly after Sinaga took him into his bedroom.

A spokesman for GMP said: “Police were called to the flat to reports of a disturbance and yes it does appear that Sinaga did not want to take any action with regards to arrests or charges.

“The man was asked to leave and was arrested for being drunk and disorderly but this was based on his behaviour outside the building a short time later rather than the disturbance with Sinaga. There is no evidence to link this man to Sinaga as a potential victim and the man has no memory of the disturbance.”

On another occasion the flatmate remembered breaking up a fight between Sinaga and another “very drunk” young man . “I think he thought Rey had tried to touch him and he didn’t really know why he was there,” the flatmate claimed, saying he found the man in their hallway in his boxer shorts.

Sinaga also called 999 on 20 February 2015 after the flatmate refused to move out. He was advised it was a “civil matter”, said the GMP spokesman.

The Guardian understands at least 30 new complainants have come forward since Sinaga was sentenced to life and told he will serve a minimum of 30 years before being considered for parole.

After his arrest in June 2017, police examined Sinaga’s multiple digital devices and discovered 3.29 terabytes of extremely graphic material – equivalent to 250 DVDs or 300,000 photos – depicting sexual assaults lasting, in one case, for eight hours. They also found what the judge, Suzanne Goddard, QC, referred to as “souvenirs” of his crimes: watches, driving licences, passports and phones stolen from his victims.

“The 195 potential victims are spread between 2005 and 2017. The evidence is a combination of stills, video (not all offences were recorded) and trophy items taken from victims,” said a GMP spokesman.

The attorney general is currently considering a request from the Crown Prosecution Service to increase Sinaga’s sentence which could see him become the first non-murderer to receive a “whole life” term.