Distinguish between serial, mass, and spree murderers. Discuss the key elements that distinguish ...

Murderers tend to be categorized as serial killers when they have killed three or more victims, in three or more separate events, at three or more separate locations, with a cooling-off period between the murders (i.e., an inactive time interval between the murders).
Mass murderers, on the other hand, kill four or more victims in one event at one location. Given that the murders take place at one time in a single location, a cooling-off period is not relevant.
Finally, for a series of murders to be considered a spree, the offender must usually have killed two or more victims in one continuous “event” at two or more locations, with no cooling-off period between the murders.