Known in London as the "Gay Sayer", Colin strived to be known as a serial killer. For this purpose he strangled five homosexual men. Robert Ressler states in "However Fights Monsters" that one has to commit five murders to become a serial killer. Colin read the book and did exactly that. He meticulously planned each murder as he set out to become a famous serial killer.

He chose gay sado-masochistic men because they were willing to get tied up before killing them. Also, he believed that the public would feel less sympathy for them. Before his arrest he taunted the cops with rambling calls claiming responsibility for the murders and threatening to keep striking once a week. He even stated "I have got the book, I know how many you have to do..."