Sinaga, 36, preyed on at least 195 men, incapacitating his victims with the date-rape drug GHB before filming his attacks

The two boys and two girls had been friends since junior school, and now they were excitedly anticipating a night out together to celebrate the end of their A-levels.

Spirits were high as the mother of Peter, one of the boys, dropped them off in Manchester city centre.

University beckoned but, for now, brimming with youthful enthusiasm, the youngsters simply wanted to have fun.

As they climbed out of the car, they were urged to 'stay together', and it was the safety of the girls as much as Peter, 18, her strapping, 6ft rugby-playing son, that was uppermost in his mother's mind.

But no one could have possibly foreseen how this joyous celebration would turn out.

Having become separated from his friends later in the evening, Peter (not his real name) was lured away, drugged and raped by Reynhard Sinaga, a geeky, slightly built, perpetual student – now known as the world's worst serial rapist.

Sinaga, 36, preyed on at least 195 men, incapacitating his victims with the date-rape drug GHB before filming his attacks.

Jailing him for 30 years earlier this month, a judge branded him a 'monster'.

The victims were almost always straight men, and they often had no inkling of what had happened when they awoke after Sinaga's appalling attacks, feeling groggy and disoriented. In fact, 70 of them have yet to be identified.

But for Peter's bravery, Sinaga's crimes might never have come to light.

Unlike the other victims, possibly because he hadn't drunk that much, Peter came round midway through the assault on him and fought for his life, furiously laying into Sinaga until he lay motionless on the floor.

Bottles of alcohol which were used to spike victims in the home of Reynhard Sinaga in Manchester

He recalls: 'I thought I may have killed him. He was not moving. I had beaten him so badly that it was borderline. I did what I had to do in that moment to survive. My instincts were kicking in, the adrenaline was going through my body just to survive.'

After escaping Sinaga's scruffy flat, Peter called his mother, asking her to return to the spot where she had dropped him and his friends six hours earlier. Initially it was Peter rather than Sinaga, who comes from a wealthy Indonesian family, who was arrested. He spent 11 hours in a cell before police discovered that Sinaga had filmed attacks on dozens of unconscious men on his iPhone, proving Peter was telling the truth.

It is a measure of his courage that, months later, this thoughtful, softly spoken young man chose to look his attacker in the eye in court rather than give his evidence from behind a screen that would have hidden him. Not only that, the day after the attack and anxious to cling to some sense of normality, Peter played for his rugby team – a decision he admits was made in part to block out the ordeal.

His parents remain fearful of the attack's residual effects and worry about some future psychological reckoning – the court heard that some of Sinaga's victims suffered 'deep and lasting psychological harm', and two attempted suicide.

Peter, now 21, has left university – during his time there he confided in his girlfriend about what happened – and is now making his way in the world, working as a sports coach. Mild-mannered and, outwardly at least, seemingly unaffected, he baulks at the word 'hero' but says the knowledge that his actions brought Sinaga to justice has helped his recovery.

The bedroom floor, where dozens of rapes took place, in the home of Reynhard Sinaga in Manchester

Recalling the night of the attack – June 1, 2017 – Peter describes how he and his friends had a drink in a pub before heading to a popular student night at a nearby club called Factory.

By about 12.30am, he had become separated from his friends and, hot and sweaty, decided to go outside for some fresh air. He was 'tipsy', after three lagers and two vodka and lemonades, but not drunk as he sat down on a low wall in an alleyway trying unsuccessfully to raise his friends on the phone.

It was at this point that a small, young-looking man approached him and started chatting.

'I thought he was just a student out having a drink,' says Peter.

'He said his name was Rey and he started talking about what I was doing at college. We were having a chit-chat for about ten minutes or so. He told me he was a uni student.'

Jailing him for 30 years earlier this month, a judge branded Sinaga (pictured) a 'monster'

Sinaga, in glasses and with a floppy fringe, appeared unassuming and friendly. Peter did not suspect anything untoward. 'I get on with people quite easily,' he explains. Sinaga asked Peter if he wanted to call his friends from his flat – just 100 yards away. As the night was getting chilly, Peter agreed.

He remembers the flat on the third floor of a ten-storey block being small and messy, typical student digs. There was a bedroom with a double bed and a desk, a kitchen area and a bathroom.

Peter says: 'I went to the toilet and when I came out he'd poured two shots of a clear liquid like vodka or sambuca, I'm not sure what it was. We had that and we carried on chatting.

'He said he was from Indonesia and came over as a student. He seemed totally normal.'

Sinaga poured another shot of what Peter recalls was a red liquid. Within minutes of downing it, he began to feel dizzy and nauseous.

He says: 'I couldn't think straight. I said that I needed to speak to my friends, I had to get hold of them and tell them I'm not feeling well. But he said, 'No, you're all over the place, you are in a state and you can't go outside.'

'It felt like I was really drunk. I was seeing four or five images of him and everything in the room was just spinning.'

Peter reached for his phone but Sinaga stopped him.

'He said, 'No, stop, you need to sit down and relax, you're not in a good state to do anything.' He was very calm and caring.'

Peter adds: 'I was thinking that I'd been an idiot and got myself into a terrible state. I was thinking, 'What am I doing here?' I didn't want to pass out in some guy's house. I wanted to phone my mum and say I want to go home.'

It was at this point that Peter passed out and collapsed in the doorway of the toilet. It is now known that he was out cold for almost four hours.

He remembers waking up face-down on a quilt on the bedroom floor.

Speaking quickly, and with his voice trembling, he describes the horror of realising the person he thought of as a Good Samaritan was sexually assaulting him. 'I was disoriented, face-down on a pillow,' he says. 'I remember my pants and jeans were down to the top of my knees.

'He was on top of me with his pants down. I turned my head to the side and he jumped up and ran out of the room.

'I stood up and pulled my pants and jeans up and I did my belt up. I was still unsure where I was – I didn't know what had happened.

'He came back in to the bedroom. He had put some trousers on. I said to him, 'Mate, what's happening? I just want to go home.' The next thing he started shouting, 'Intruder! There's an intruder.' I said, 'Mate, can you calm down? What's happening?' I was so confused.'

Predator: A CCTV image of Reynhard Sinaga in a corridor at the flats where he attacked men

Then Sinaga ran at him, headbutting him across the bridge of his nose, before biting him on the shoulder and stomach.

Peter fought back. 'We were wrestling and grappling with each other. I managed to hit him a few times over the head. I was hitting him and elbowing him and just trying to get him off me.

'I was stronger than him and I pushed him on to the bed. He grabbed a hold of my T-shirt and pulled me down on top of him. He was grabbing hold of me and biting me. I hit him a few more times and he lay on the bed.'

With Sinaga dazed, Peter frantically scrambled his belongings together. 'I walked out of the bedroom and found my phone in the bathroom with my driving licence and my wallet. He must have taken them out of my pockets when I was passed out,' he says. 'I knew I had to get out of there and so I went to open his front door.'

Just as Peter discovered the door was locked, Sinaga suddenly sprang back to life and jumped on his back. Peter pulled him over his shoulder and began raining down punches on the rapist's head. 'I'd had scuffles on the rugby field before but nothing like this,' he says. 'I was punching him in the head and finally he let go of me. I got the front door open and ran out.'

Just as Peter (pictured) discovered the door was locked, Sinaga suddenly sprang back to life and jumped on his back

By now, Peter's blue jeans and black T-shirt were drenched in Sinaga's blood. He checked his phone but it had run out of battery so he ran across the road and stopped a startled passer-by. After pleading to borrow his phone, he called his mother. 'I said, 'Mum, please can you pick me up where you dropped me off?' '

As he waited he thought to himself that his attacker might be dead. He says: 'He wasn't moving and I thought about the amount of force I'd used to get him off me.

'For a second I thought about not calling the police because I was worried I was going to be in trouble, but I knew I had to. I needed to tell them what had happened.'

Peter went back inside the block of flats and knocked on an apartment on the first floor.

'This guy came to the door and I said, 'Please can I use your phone? I need to phone the police.' He loaned me his mobile and he was watching me carefully. I phoned 999. I said, 'I think I've been raped and that I've beaten this man up in his apartment.'

When Peter's mother arrived 20 minutes later, she was confronted by blue flashing lights outside the flats.

Sinaga was lying in a pool of blood in the hallway of his flat and Peter recalls hearing a voice over an officer's radio saying: 'We've found him – he's not looking good.'

It was at this point that Peter was arrested on suspicion of grievous bodily harm.

Asked to turn out his pockets, he was surprised to find a white iPhone 4 in the back pocket of his jeans. During the melee in the flat, the teenager had mistakenly grabbed Sinaga's old phone.

It turned out to be a vital discovery – it contained videos and images of dozens of men that Sinaga had drugged and raped over the previous two-and-a-half years.

Police also found that a second iPhone in Sinaga's flat had been used to record him raping Peter – supporting his claim that he was acting in self-defence.

However, the discovery of the footage came too late to prevent the teenager facing intense questioning. 'They saw how beaten up Sinaga was and they just assumed I was the perpetrator, that I had come and beaten up some little Asian guy who is half the size of me. The police were asking me if I am homosexual or straight. I said I'm straight.'

Peter is surprised that the police did not take blood samples from him that day, considering he had told them of his fears that he had been raped.

'I think if I had been female then they probably would have done some tests,' he says.

After 11 hours in custody, Peter was released on police bail and allowed to go home.

Later, he was told of the discovery of the second phone – a black iPhone 6 from under Sinaga's bed. The rapist had – eventually – told police officers its passcode and on it they found a video of the attack on Peter.

Meanwhile, analysis of the phone found in Peter's pocket and a hard drive also recovered from Sinaga's flat revealed 3.3 terabytes of digital evidence – the equivalent of 250 DVDs.

Indeed, Sinaga's victims were so numerous that his case had to be split into four separate trials. Peter says: 'The police said there were hundreds of videos. I couldn't believe it. I felt sick.'

Despite the vast quantity of evidence, Sinaga denied his crimes, forcing victims to give evidence. His defence – that they were all willing participants in a bizarre sexual fantasy where they pretended to be asleep while he had sex with them – was described in court as 'preposterous'.

Peter says he quickly decided he would not let what Sinaga did to him ruin his life, particularly after going through yet another ordeal – an HIV test. He says: 'I was tested for HIV and other things as part of the process. It was a big relief when they came back clear.'

And he explains: 'If I let this change me then he has won.'

Part of the reason for his sanguine outlook, it appears, is the immediate retribution he meted out to Sinaga by waking up and battering him in the flat.

'In their victim statements, all of the other people said this had changed them and ruined them all. I don't feel like that at all.

'I feel like I woke up and stopped him, I beat him. I managed to stop him – I feel like I got payback.'

He has refused to watch the footage of the attack on him by Sinaga, adding: 'The police asked me if I wanted to see my video and I said no – no one wants to watch that.' He has confided in close friends and immediate family members, but few others. Not his grandparents, or his rugby team-mates.

In the intervening months, life carried on as normal until Sinaga's trial began. Almost a year to the day since the rape, Peter was called to give evidence at Manchester Crown Court.

He says: 'I wanted to look him in the eye. I was excited – this was my day in court to put him away. He didn't seem to show any remorse. He was trying to laugh and joke with the prison guard who was in there with him, who wasn't really giving him the time of day.'

Sinaga was convicted of Peter's rape, and over the next 18 months he faced a further three trials where he was found guilty of 136 rapes of 48 men. He was jailed for life with a minimum term of 30 years, but the Attorney General has asked for his sentence to be reviewed by the Court of Appeal, which could increase it to a whole-life term – meaning he will never be released.

For Peter's part, he now wants to concentrate on his own future. He says: 'I've had my day in court and now he is stuck in Strangeways [prison] while I'm out living my life. I'm still me, I'm getting on with my life.' And he adds: 'He shouldn't see the light of day ever again. If he does it will be too soon. He has never shown any remorse. He should die in prison.'

Anyone with information about the Sinaga case can contact Greater Manchester Police on 101. St Mary's Sexual Assault Referral Centre, 0161 276 6515.

The moment I feared my gentle boy would be jailed for murder: Mother of teenager who fought off world's worst rapist thought his life was over when police called to say they had to talk to him urgently

The mother of the teenager who fought off Reynhard Sinaga has described the chilling moment she thought the serial rapist had died – and how she feared her son would be charged with his murder.

As he came round after being drugged by Sinaga, Peter fought frantically to escape, lashing out with punches and leaving the Indonesian student with a suspected bleed on the brain.

Police had initially been sceptical of Peter's story of being raped, so when a detective rang his mother a day later saying they needed to speak to him urgently, she feared the worst.

She said: 'That phone call was the moment I thought, 'Oh my God, this guy has died' and that my son was going to prison. I thought my son's life was over.'

The mother of the teenager who fought off Reynhard Sinaga has described the chilling moment she thought the serial rapist had died – and how she feared her son would be charged with his murder

It soon transpired, however, that Sinaga was alive and recovering well in hospital. But instead of being able to savour the relief, Peter and his family were then horrified to learn that he had been sexually assaulted.

A video found on a mobile phone showed Sinaga abusing Peter as he lay drugged and unconscious in Sinaga's grubby flat in Manchester.

In a profoundly moving interview, Peter's mother spoke of her pride in the way her son coped following the attack and his courage in facing Sinaga down in court. But she is beset by fears that her son, despite 'putting on a brave face', may be 'bottling' up his emotions.

In tears she said: 'I get emotional when I think about him being so brave and what he has gone through. Everybody deals with things differently. It has affected some of the lads [the other victims] quite a lot mentally.

'I hope it is not a front. I don't think it is because of his personality and the way he behaves has not changed. I think he is living in denial a bit because he has just been told what happened to him – he has no physical memory of it happening to him.

'In his mind, he woke up in time and fought the guy off and that's the way he deals with it. He didn't want to see the video because that would have made it real. This is why I think he has remained his chirpy and bouncy self.'

She added: 'I was really pleased when he got a girlfriend when he went off to university because I was wondering if this might have put him off or changed him.

'It was a good sign for me that he was moving on and being a normal lad and doing what normal 19-year-olds do.'

That may be so, but Peter's mother said she and her husband continue to keep a close eye on him for any sign that he may start to struggle with what happened. There have been moments that have caused them to pause for thought. 'One of his ex-girlfriend's best friends was an Indonesian gay guy who looked similar to Sinaga,' the mother said. 'He did have some issues at first with him – he didn't trust him.'

She revealed she was at first cross with her son when he called her at 5.20am on June 2, 2017, and pleaded with her for a lift.

She drove to pick him up, not knowing the horrifying ordeal he had been through. But when she arrived at the block of flats her son had directed her to, she was confronted by a scene that would strike fear into the heart of any parent.

She described seeing flashing blue lights and 'police everywhere' before spotting her son speaking to officers in the foyer.

She recalled: 'I could see his T-shirt was all pulled around his neck and I said to him, 'Is that your blood? Whose blood is that?'

'That's when he said, 'I think he was trying to rape me.' I just froze at that point.'

She was asked by officers to drive her son to a nearby police station and on the way Peter opened up about what had happened to him. She said: 'I was saying to him, 'What the hell happened? You could have been killed.'

'He was saying, 'He wouldn't let me out. I think he was trying to rape me.' '

Within two days Peter would go from being treated as a suspect to a rape victim.

As the full horror of Sinaga's depravity began to emerge, Peter was called back to the police station and given the news that a video showed Sinaga raping him at the flat. The devastated teenager asked a policewoman to break the news to his mother.

His mother said: 'A policewoman took me into a side room and sat me down and told me what they had found. We are not a family of screamers and shouters – we don't burst into tears.

'I just had a numb feeling, like what do we do now?

'I am quite a calm person, like my son, but his dad is more of a hot-head. When we got home I told him that police had found a rape video he was yelling and calling Sinaga names, saying, 'that dirty b******.' He was really angry.'

She said the traumatic experience had made the family, who live in a neat, three-bed semi-detached house in the suburbs of Manchester, stronger. 'We have gone through it together and supported each other through it,' she said. 'His sister was only 16 when all of this first happened but we didn't keep it from her.

'We didn't want to keep asking him if he was OK… His dad is a bit more worried when Peter is out. He will be checking his phone and following Peter's social media updates about where he is and making sure he is not alone.

'I don't get too worried. He's not going to put himself in that situation again. He has a really lovely bunch of mates – girls and boys – and they have been amazing.'

But she added: 'I do worry if what happened could affect him in later life. We are all keeping a close eye on him.'