The most prolific substantiated modern serial killer is Pedro López. Born in Colombia, he raped and killed young girls in Colombia, Peru and Ecuador, eventually confessing to 300 such murders. Charged on 57 counts of murder in Ecuador, the Monster of the Andes was sentenced in 1980 to life imprisonment.

According to the National Centre for the Victims of Crime, mass murderers differ from serial murderers in that the former appear to suddenly act out and indiscriminately kill numerous people in a specific time period.



Whereas the official FBI definition for serial homicide is: Three or more separate events with an emotional cooling off period between homicides, each murder taking place at a different location.