Dennis Nilsen, a British serial killer convicted of murdering six men and attempting to murder two more, once tried to strangle a Hong Kong student, Andrew Ho. Ho was able to flee and report the event to the authorities. Ho chose not to charge Nilsen after questioning him.
Nilsen's crimes were not revealed until 1983, when police were called to his home after drains were found to be clogged with human flesh. Nilsen had been flushing his victims' remains down the toilet, and the clog was caused by the accumulation of corpses.Nilsen admitted to the killings and was sentenced to life in prison.
He passed away in 2018 at the age of 72.