The phenomenon of serial killings has been recognized since a man dubbed "Jack the Ripper" murdered seven London prostitutes in 1888. The FBI terms serial killings as serial murders and as the killing of several victims in three or more separate events. These may occur several days, weeks, or years apart, and reveal similarities of pattern, such as where the murders occurred, the type of victim, or the method of killing.
The elapsed time between murders separates serial killers from other multiple killers. John Wayne Gacy, a serial murderer, planned the separate killings of 33 boys and young men in Chicago over a span of two to three years in the late 1970s. Other serial murders have been attributed to Albert De Salvo, the Boston Strangler, although he was never charged with murder; Theodore Robert Bundy; Jaun Carona; David Berkowitz, Son of Sam; Wayne Williams of Atlanta; and Randy Kraft.
Serial killers and mass murderers often display the same characteristics of being manipulative and uncaring people. What differentiates the two is the timing and numbers of the murders. Serial killers commit murder over a long period of time, and often in different places, while mass murderers kill within a single location and timeframe.
Raymond Martinez Fernandez and Martha Jule Beck were an American serial killer couple. They are believed to have killed as many as 20 women during their murderous spree between 1947 and 1949.
The Moors murders were carried out by Ian Brady and Myra Hindley between July 1963 and October 1965, in and around what is now Greater Manchester.
Fred & Rose turned their children and guests into sex slaves and murdered them when they tried to escape.
Gerald Gallego and Charlene Gallego
Gerald and Charlene kidnapped and killed ten people, mostly teenage girls, lured and captured in well-planned schemes, the ultimate goal of which was to provide a steady procession of disposable "love slaves."