Sinaga was convicted of 136 counts of rape, 14 counts of sexual assault, eight counts of attempted rape and one count of assault by penetration. His defence barrister said that he could offer no mitigation. In the first two trials he was given 88 concurrent life sentences with a minimum 30-year term before being considered for parole. This was raised to 40 years by the Court of Appeal on 11 December 2020. Reporting restrictions were in place until the conclusion of his last trial, after which his crimes were made public for the first time. Detectives subsequently set up a hotline with the expectation that dozens of new victims could come forward. Sinaga was originally held at HMP Strangeways, and reported as refusing to cooperate with investigators. He was moved to HM Prison Wakefield in April 2020, several months after his final trial.
