The "Zebra" murders were a string of racially motivated murders that took place in San Francisco, California, from October 1973 to April 1974. A group of male Black Muslims who called themselves the "Death Angels" committed at least 15 murders and 8 attempted murders, mostly against white victims. However, some authorities believe they may have killed as many as 73 or more victims. Criminology professor Anthony Walsh wrote how "The San Francisco–based Death Angels may have killed more people in the early to mid-1970s than all the other serial killers operating during that period combined." Police named the case "Zebra" after the special police radio band they assigned for the investigation.