Nilsen's murders were first discovered by a Dyno-Rod employee, Michael Cattran, who responded to the plumbing complaints made by both Nilsen and other tenants of Cranley Gardens on 8 February 1983. Opening a drain cover at the side of the house, Cattran discovered the drain was packed with a flesh-like substance and numerous small bones of unknown origin. Cattran reported his suspicions to his supervisor, Gary Wheeler. As Cattran had arrived at the property at dusk, he and Wheeler agreed to postpone further investigation into the blockage until the following morning. Prior to leaving the property, Nilsen and fellow tenant Jim Allcock convened with Cattran to discuss the source of the substance. Upon hearing Cattran exclaim how similar the substance was in appearance to human flesh, Nilsen replied: "It looks to me like someone has been flushing down their Kentucky Fried Chicken."

At 7:30 a.m. the following day, Cattran and Wheeler returned to Cranley Gardens, by which time the drain had been cleared. This aroused the suspicions of...