His motive remains unclear, though some have said that he was taking revenge on prostitutes because he'd once been swindled by one. The Yorkshire Ripper himself said that the voice of God commanded him to kill. His method of murder remained fairly consistent throughout his spree.

What made Peter Sutcliffe kill?

He argued he was the tool of God's will and had heard voices instructing him to kill prostitutes as part of a "mission". Sutcliffe claimed he first heard God's voice when he worked as a gravedigger at Bingley Cemetry in 1965 and again in 1967.

Why did the Ripper kill his victims?

By then, London's Scotland Yard police had determined the pattern of the killings. The murderer, offering to pay for sex, would lure his victims onto a secluded street or square and then slice their throats. As the women rapidly bled to death, he would then brutally disembowel them with the same six-inch knife.