The Yorkshire Ripper. In the 1970s, a serial killer would begin murdering women in places like Leeds and Bradford in the UK. The police would make assumptions and errors in judgment which would allow the killer to continue murdering far longer than otherwise may have been the case. His weapons were hammers, screwdrivers, & knives. He murdered thirteen and injured another seven. What motivated Peter Sutcliffe to kill? Did a prostitute short him some money? Did God instruct him to kill these women as he has also claimed? In the end, this case had a profound effect on how the police investigate serial murderers.