A serial killer is, traditionally, a person who has murdered three or more people over a period of more than a month, with down time (a “cooling off period”) between the murders. Some sources, such as the FBI, disregard the “three or more” criterion and define the term as “a series of two or more murders, committed as separate events, usually, but not always, by one offender acting alone” or, including the vital characteristics, a minimum of two murders.
Below is a list of serial killers and their FBI files, obtained under the Freedom of Information Act / Privacy Acts.
Declassified Serial Killer FBI Files
  Baumeister, Herb – [ 164 Pages, 4.92MB ] – Herbert Richard “Herb” Baumeister (April 7, 1947 – July 3, 1996) was an American serial killer from Westfield, Indiana outside of Indianapolis. Baumeister committed suicide before he could be brought to trial, and never confessed to the crimes he was alleged to have committed. He killed a confirmed 9, with a suspected 11 more. |
 Bundy, Ted – [ 145 Pages, 6.37MB ] – In 1977, Theodore (or Ted) Robert Bundy (1946-1989) escaped from custody while being transported to Colorado to stand trial for murder. Salt Lake City issued an escape warrant that prompted the FBI’s involvement. |
 Cunanan, Andrew – [ 718 Pages, 25.53MB ] – Andrew Phillip Cunanan (1969-1997) was a serial murderer placed on the FBI Ten Most Wanted List. These materials consists of a previously released FBI Minneapolis Field Office file concerning the hunt for Cunanan between May and July of 1997. |
 Dahmer, Jeffrey – [1,220 Pages, 101MB] – Jeffrey Lionel Dahmer (May 21, 1960 – November 28, 1994), also known as the Milwaukee Cannibal, was an American serial killer and sex offender, who committed the rape, murder and dismemberment of 17 men and boys between 1978 and 1991, with many of his later murders also involving necrophilia, cannibalism and the permanent preservation of body parts—typically all or part of the skeletal structure. |
 Defeo, Ronald – [7 Pages, 1.5MB] – Ronald Joseph DeFeo Jr. (September 26, 1951 – March 12, 2021) was an American mass murderer who was tried and convicted for the 1974 killings of his father, mother, two brothers, and two sisters in Amityville, Long Island, New York. Condemned to six sentences of 25 years to life, DeFeo died in custody in 2021. The case inspired the book and film versions of The Amityville Horror. |
 Gacy, John Wayne – [20 Pages, 1.45MB] – John Wayne Gacy Jr. (March 17, 1942 – May 10, 1994) was an American serial killer and rapist. He sexually assaulted, tortured and murdered at least 33 teenage boys and young men between 1972 and 1978 in Cook County, Illinois (a part of metropolitan Chicago). All of Gacy’s known murders were committed inside his Norwood Park ranch house. His victims were typically lured to his address by force or deception, and all but one of his victims were murdered by either asphyxiation or strangulation with a makeshift tourniquet; his first victim was stabbed to death. Gacy buried 26 of his victims in the crawl space of his home. Three other victims were buried elsewhere on his property, while the bodies of his last four known victims were discarded in the Des Plaines River. Convicted of 33 murders, Gacy was sentenced to death on March 13, 1980, for 12 of those killings. He spent 14 years on death row before he was executed by lethal injection at Stateville Correctional Center on May 10, 1994. Gacy became known as the “Killer Clown” because of his charitable services at fundraising events, parades, and children’s parties where he would dress as “Pogo the Clown”, a character he had devised. |
 Jack the Ripper – [ 8 Pages, 0.7MB ] – In 1888, a series of unsolved homicides in London, England were attributed to a serial killer called “Jack the Ripper.” In 1988, Supervisory Special Agent John Douglas of the FBI’s National Center for the Analysis of Violent Crime performed an analysis of the case for the Cosgrove-Meurer Production Company. This release consists of his analysis. |
Mention the term serial killer and what comes to mind for many people are murderers like Ted Bundy and John Wayne Gacy, whose grisly deeds seem to haunt our collective imagination.
But when Bob Morton considers serial killers—which he has spent much of his professional life doing—the recently retired special agent formerly with our Behavioral Analysis Unit thinks mostly about statistics.
Morton, the author of a new study on serial murder for the FBI’s National Center for the Analysis of Violent Crime, spent the last eight years gathering and analyzing details from hundreds of serial murder cases to help investigators better understand these terrible crimes—and be better equipped to solve them.
“In the past,” Morton said, “research tended to focus on known offenders and what led them to become serial murderers.” That information, while useful, provided little help to investigators trying to apprehend an unknown offender in an active, unsolved case.
The new study—Serial Murder: Pathways for Investigations—focuses on a key aspect of serial murder cases: how and where the victims’ bodies are discovered and what that says about the killers.
“What we tried to do was give investigators working these cases a common place to start, which is the body,” Morton said. “You work your way back from there to discern offender characteristics and narrow the suspect pool. The body is the only constant in the crime,” he explained. “Lots of other things can change, but how you find that victim is not going to change.”
If the victim was a prostitute, for example, and the body was left where the murder occurred, that may offer certain clues about the killer. If the body was hidden at a distance from the murder site, that may offer different clues. The study’s statistical data was drawn from 480 U.S. serial murder cases involving 92 offenders over a period of nearly five decades. Morton believes the study’s findings could be a “game changer” for investigators working unsolved cases.
“Many of the things we have learned over the years through experience we are trying to prove through empirical research,” he said. “The main goal is to provide law enforcement with relevant data that helps them focus on the most likely suspects.”
Serial murder in the United States is surprisingly rare. Although it’s impossible to quantify the number of active serial murderers nationwide or how many murders they commit, academic and law enforcement research suggests that the numbers of homicides carried out by serial offenders in a given year are a fraction of the total number of murders that occur in the U.S. “But when it does occur,” said Morton, who has worked dozens of these cases during his 25-year Bureau career, “it can be overwhelming to a community and its law enforcement agencies.”
“There is a lot of pressure on the police to solve these crimes,” he added, and most local police departments haven’t had a serial homicide in their jurisdiction. That’s where the FBI can provide behavioral-based investigative support to our state and local partners. The National Center for the Analysis of Violent Crime and members of our Behavioral Analysis Unit have extensive experience with serial murder investigations and offer their expertise on request.
“The FBI has become a clearinghouse for these crimes,” Morton said, “and we stand ready to assist local law enforcement when they are faced with an active serial murder case. This new research is one more tool to help investigators.”
Serial Murder: Pathways for Investigations [ 78 Pages, 3.01MB ]
