Analysis of information sources in references of the Wikipedia article "Asasino en serie" in Galician language version.
Serial killing has been defined by different researchers or groups as either two or more, three or more, or even four or more people killed over at least one month with a cooing off period between each of the murders.
A person who murders 3+ people over a period of > 30 days, with an inactive period between each murder, and whose motivation for killing is largely based on psychological gratification.
