LONDON — A man convicted of drugging and sexually assaulting 48 young men in Manchester, and videotaping and cataloging the rapes, was sentenced Monday (Jan 6) to life in prison, closing a series of trials against a man whom prosecutors called “the most prolific rapist ever tried in a British court.”

The man, Reynhard Sinaga, 36, was found guilty of carrying out a 2 1/2-year campaign in which he approached scores of drunk young men outside Manchester clubs and lured them back to his nearby apartment under the guise of giving them a place to sleep or recharge their phones.

Instead, he gave them drinks spiked with sedatives, prosecutors said, before poking their belly buttons to make sure they were unconscious and then raping them, sometimes for hours.

Apart from victims noticing that they had particularly bad hangovers the next morning, Sinaga committed the rapes without anyone noticing until a June morning in 2017 when an 18-year-old man woke up in the middle of being assaulted.

The man beat up Sinaga and escaped with his attacker’s white iPhone. On Sinaga’s digital devices, investigators said they eventually found huge volumes of photos and videos of his assaults, sometimes cataloged alongside pictures of a victim’s ID card.

In most cases, prosecutors said, the victims did not know exactly what had happened to them until getting a visit from the police.

Investigators found evidence of Sinaga assaulting more than 190 victims in all, they said. Detectives have failed to identify 70 victims and are still looking to speak to them.

On Monday, at the end of Sinaga’s fourth trial, the courts lifted a media blackout that had previously kept his name from being publicly reported.

Sinaga was already serving a life sentence with a minimum of 20 years before parole after being convicted in his earlier trials, which began in 2018. He was sentenced Monday to life in prison and had his minimum term increased to 30 years.

Sinaga insisted on taking the case to trial and argued in court that the victims were only pretending to be asleep as part of a sexual role play. He accused the victims of being closeted gay men lying about the assaults, according to British news accounts of the trial.

Each of Sinaga’s four trials dealt with between 10-13 victims. In all, he was found guilty of 159 offenses, including 136 anal rapes.

“He would no doubt still be adding to his staggering tally had he not been caught,” Ian Rushton, a deputy chief crown prosecutor for the northwest of England, said in a statement. He said Sinaga “appears to have derived further twisted pleasure from rewatching his films in court and putting victims through the trauma of giving evidence.”

Born and raised in Indonesia, Sinaga came to Britain in 2007 on a student visa. He studied for a master’s degree at Manchester University in sociology, and then began studying for a doctorate in human geography in 2012 at Leeds University.

Living off money given to him by his father, a banker in Indonesia, Sinaga fashioned a life of nights out and holidays that looked extravagant to his friends, according to British news accounts of trial testimony. He was openly gay, and he attended gay clubs in Manchester and used gay hookup apps, Sinaga testified.

Sinaga’s friends’ only hint of his nighttime campaign was the way he boasted of making heterosexual men realize their gay fantasies.

“He was straight in 2014,” he texted one friend of a victim, prosecutors said. “2015 is his breakthrough to the gay world hahaha.”

In another text, he said, “Take a sip of my secret poison, I’ll make you fall in love.”

But in secret, Sinaga collected the evidence that ultimately proved prosecutors’ case against him. He kept some men’s belongings as trophies, prosecutors said. He stored films of the assaults on two cellphones. He looked his victims up on Facebook afterward and tried to add them as friends.

And some agreed. One was so oblivious about what had happened that he returned with his girlfriend to Sinaga’s apartment the next day, trying to prove to her that he had only been recovering from a night out and not sleeping with another woman, British news reports said.

For the most part, prosecutors said, Sinaga stuck to a consistent pattern in his attacks. After midnight, he lingered outside clubs, waiting for mainly heterosexual young men who had been separated from their friends or kicked out by bouncers.

Preying on their various needs — their phone batteries had died, or they had run out of money for a taxi home, or they were sick from drinking — Sinaga convinced them to follow him home, where he said they could sleep on the floor or have a few more drinks.

Once there, investigators believe Sinaga was probably drugging his victims with gamma-hydroxybutyric acid, or GHB, which is sometimes used recreationally as a club drug.

At his hearing in Manchester Crown Court on Monday, Judge Suzanne Goddard said she had considered sentencing Sinaga to a life term without the possibility of parole — an unprecedented punishment for a crime other than murder — before settling on the 30-year minimum term, British news reports said.

“In my judgment you are a highly dangerous, cunning and deceitful individual who will never be safe to be released,” the judge said, “but that is a matter for the Parole Board.” THE NEW YORK TIMES