The last body Nilsen dissected-that of Stephen Sinclairgot the same treatment as the two preceding it. He boiled the head, hands, and feet, and placed the rest in plastic bags. He put one part in a cubbyhole in the bathroom and others went into the tea chest. Some of the flesh and organs were flushed down the toilet.
Nilsen may also have dumped some large pieces, because a man found a bag ripped apart near his garden, some distance away from Nilsen's, which contained what looked like a rib cage and a spinal column. He did not report it and it disappeared within a few days. It was never tied to Nilsen.
There were five other tenants at 23 Cranley Gardens, but none of them knew Nilsen very well. During the first week of February, one of them noticed that the downstairs toilet was not flushing properly. He tried to clear the blockage with acid, to no avail. Other toilets seemed to be functioning as poorly, but Nilsen denied that he was having any problems. A plumber arrived to investigate, but his tools did not work. He called in a specialist.
Nilsen feared that his own activities might be at the heart of the problems downstairs, so he stuffed the rest of Sinclair's body into plastic bags, along with the partially boiled head. He locked the remains into the closet. He stopped flushing the toilet.
Two days later, in the evening, a company called Dyno-Rod arrived to examine the blockage. Deciding it was underground, the technician, Michael Cattran, went into a manhole by the side of the house.
He noticed a peculiar smell. Cattran was convinced it was from something dead. He spotted sludge about eight inches thick on the floor of the sewer and found that it was composed of thirty to forty pieces of flesh. It had come from the pipe leading from the house. He reported his find to his superiors. The tenants gathered around him as he phoned, including Nilsen, and he mentioned that they might have to call the police. First, however, his company would do a better analysis by daylight. He then took Nilsen and one of the other tenants back outside with him to see the pile of rotting flesh.
Nilsen returned at midnight to remove the particles of flesh and dumped them over the fence. He thought about replacing them with pieces of chicken from the store, and then pondered suicide. Instead he sat alone in his flat and drank, surrounded by the body parts of three men.
However, the downstairs tenants had noticed his movements. When Cattran returned and found the sewer cleaned out, the tenants told him their suspicions. From deep inside the sewer, he pulled out one piece of foul-smelling meat and called the police.
At work on the day of February 9, 1983, Nilsen told a co-worker, "If I'm not in tomorrow, I'll either be ill, dead, or in jail." They both laughed.
But Nilsen sensed something coming. When he stepped into the dark hallway to go to his flat, he saw three men waiting for him.
Detective Chief Inspector Jay told him they had come about his drains. He told Nilsen that human remains blocked them.
Nilsen exclaimed in dismay, and then asked, "Where did it come from?"
They pointed out that it could only have come from his own flat, and asked about the rest of the body.
Nilsen gave up and said he would come to the station. He knew his rights and admitted that he wanted to talk, and talk he did, as he unburdened himself in sickening detail. The more he talked, the more the police realized that they had been given clues over the past four years and had they acted differently, might have stopped the killing spree much sooner.
A search of Nilsen's closet uncovered several bags of male remains in various stages of decomposition.
These were taken to a mortuary for examination. Nilsen told them to look in the tea chest and under a drawer in the bathroom. He also pointed them toward his former apartment where he had killed "twelve or thirteen" men. He admitted that there were seven others whom he had tried to kill and had failed.
In the police station, Nilsen said, "The victim is the dirty platter after the feast and the washing up is an ordinary clinical task."