Final answer:
The murders by Bernardo, Olson, and Manson are examples of serial murders, involving multiple killings over time with a psychological element in victim selection.
Step-by-step explanation:
The brutal murders committed by Paul Bernardo, Clifford Olson, and Charles Manson are cited as examples of serial murders. Serial murders are defined as a series of killings committed by a person or persons over a period of time, with a cooling-off period between each murder.
Unlike mass murders, which occur at a single location or event, serial murders involve victims that are selected over a broader timeframe and often have a psychological link that dictates selection of the victims. Neither spree killings, which occur without a cooling-off period, nor terrorism, which has political aims, accurately describe the actions of Bernardo, Olson, and Manson.