Serial killer

A serial killer is an individual who commits multiple murders. Most researchers use a baseline of three or more murders to define this group. These killings must occur in separate events over a period longer than one month. They also usually happen in different locations. The Federal Bureau of Investigation (FBI) uses a slightly different standard. In 2005, experts at an FBI symposium in San Antonio, Texas, settled on a specific definition. They define serial murder as the unlawful killing of two or more victims by the same offender in separate events. This change was supported by researcher Enzo Yaksic. He noted that these killers often share similar pathologies, or mental patterns.

It is important to distinguish serial killers from other types of offenders. A spree killer engages in many killings over a period of days or weeks. The main difference is the cooling-off period. A cooling-off period is a significant break between murders where the killer returns to a normal life. Spree killers do not have this break. Some experts even suggest a hybrid category called a "spree-serial killer" for those with extended bouts of killing. Other categories include mass murderers and contract killers. While these groups overlap, the element of time is the primary way to tell them apart.

Serial killers are driven by many different motives. The FBI states that motives can include anger, thrill-seeking, or attention seeking. Some killers may also act for financial gain. These individuals often have various personality disorders. Some may experience mental illness, such as psychotic breaks. During a psychotic break, a person might believe they are someone else. They might also believe they are compelled by other entities to commit crimes. Victims often share common traits. These can include their gender, race, or demographic profile.

History shows that serial killers have existed for many centuries. In 144 BC, a Chinese man named Liu Pengli was accused of murdering at least 100 people. He led groups on expeditions to seize belongings and kill for sport. In the 15th century, Gilles de Rais was alleged to have killed between 140 and 800 children in Europe. In 1610, the Hungarian aristocrat Elizabeth Báthory was arrested. She was accused of killing as many as 650 young women. In the 19th century, Juhani Aataminpoika killed 12 people in Finland during 1849.

Certain cases changed how society and law enforcement operate. In 1888, the unidentified Jack the Ripper killed at least five women in London. This case created a massive worldwide media frenzy. It also led to the development of modern criminal investigation techniques. Police used house-to-house inquiries and collected forensic material. Surgeon Thomas Bond even created one of the first character profiles. In the early 1890s, H.H. Holmes gained notoriety in the United States through sensationalized newspapers. In South America, Pedro Lopez killed at least 110 girls. He was known as the "Monster of the Andes."

In the United States, serial killings were very prominent from 1970 to 2000. This era is often called the "golden age of serial murder." One reason for this was urbanization. As more people moved to cities, they lived in close proximity. This also offered more anonymity to criminals. However, the number of active serial killers in the U.S. peaked in 1989. Since then, the numbers have steadily trended downward. This decline happens alongside a general decrease in overall crime in the country.

Experts suggest several reasons for the decline in these crimes. Professor Mike Aamodt attributes this to improved forensic technology. Better science helps police catch offenders more quickly. Other factors include less frequent use of parole. People are also behaving more cautiously in modern society. Some researchers also look at broader social changes. These include increased incarceration and changes in early childhood lead exposure. Understanding these patterns helps researchers study the complex relationship between society and crime.