A while ago, I was watching at national geographic about "Jack the Ripper". He is an unidentified serial killer in the year 1888. His victims were usually women allegedly earning income as prostitutes. He killed his victims during nights or dawn. Each victim has cuts on their throat after the body has mutilated. There were theories saying that victims were first strangled to remain silent and remove organs from the body... so this means that the killer is a doctor or some medical professional (these were only theories).