"Something smells off"
Nilsen was met on the evening of 9 February 1983 by Detective Chief Inspector Jay, who informed him that they wished to question him in relation to the human remains that had been discovered in the drains. On entering the flat, Jay noticed the pervasive foul odour, and asked Nilsen what it was, at which point he calmly confessed that what they were looking for was stored in bags around the flat, which included two dismembered heads and other larger body parts.
Upon his arrest, he immediately provided exhaustive details about his killing spree, admitting to killing 15 young men, despite receiving a legal caution. He also admitted to the attempted murder of seven others, although he could name only four of them. At no point did he show any remorse, and appeared eager to assist the police with amassing evidence against him, even taking them to his old address to point out specific disposal details.
After the confession, Nilsen was held at Brixton Prison pending trial. Whilst there, he wrote over fifty notebooks of his memories to assist the prosecution, and also drew what he referred to as “Sad Sketches” which detailed his treatment of some of his victims. He seemed ambivalent about his fate, at turns without remorse, and then showing concern about public attitudes towards him. He fired his legal council, then rehired him, and fired him once again, shortly before he came to trial.