Mr. 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 on Monday to life in prison and had his minimum term increased to 30 years.

Mr. 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 Mr. Sinaga’s four trials dealt with between 10 and 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 Mr. 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, Mr. 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, Mr. 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, Mr. Sinaga testified.

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