Explained: Who is Samuel Little, America’s biggest-ever serial killer?

Samuel Little during a hearing in Los Angeles in 2014. (AP Photo: Nick Ut)

The Federal Bureau of Investigation (FBI) has identified the most prolific serial killer ever to be caught in America. His name is Samuel Little; he is now 79 years old, and imprisoned for life in California State Prison in Los Angeles.

Little has been convicted of eight murders, all women, whom he killed by strangling between 1981 and 1994.

On Sunday, the FBI said that Little had confessed to killing a total of 93 women in a career of crime spanning at least 35 years from 1970 to 2005. Fifty of these murders have been verified by investigators, and the FBI said it finds "all of his confessions credible".

The murders took place at locations across the United States -- from Los Angeles in the west to Washington DC in the east, and from Homestead, Florida in the south to Willoughby Hills, Ohio, in the north, according to an interactive map which FBI has been periodically updating as the full extent of Little's crimes becomes apparent.

Before Little, Gary Ridgway, the so-called "Green River Killer", was considered to be America's worst serial killer. Ridgway was convicted of 49 murders in Washington state during the 1980s and 1990s.

The English doctor Harold Shipman is generally considered to be the worst serial killer ever to have lived. Shipman is estimated to have killed between 215 and 250 individuals, some 80% of whom were old women, between 1975 and 1998, mainly by administering drugs in lethal doses. Shipman hanged himself in his prison cell in 2004.

“For many years, Samuel Little believed he would not be caught because he thought no one was accounting for his victims,” the FBI quoted its ViCAP Crime Analyst Christie Palazzolo as saying in a report titled 'Confessions of a Killer'. “Even though he is already in prison, the FBI believes it is important to seek justice for each victim -- to close every case possible.”

ViCAP, or the Violent Criminal Apprehension Program, is the FBI unit responsible for the analysis of serial violent and sexual crimes. The FBI has sought the public’s help in matching the remaining unconfirmed confessions made by Little.

Family photographs of Carol Alford, who was murdered by Samuel Little in Los Angeles in 1987. Mr. Little has now confessed to killing about 90 women. (Source: Jae C. Hong/Associated Press)

There is extra urgency in the matter now because FBI says Little's memory has become faulty, and he is in poor health. Over the weekend, the agency released five sketches drawn by Little of women that he claimed to have killed, along with information about where he met each one of these victims.

Little was arrested many times for armed robbery, rape and kidnapping across the US. Most of his crimes were carried out in poor neighborhoods and among transient communities. Until 2014, however, he had managed to avoid a conviction for murder, and had served less than a total 10 years in prison.

The FBI has released 30 drawings of his victims -- in colour, and drawn by Little himself. Most of these portraits are of black women. On its web site, the FBI has also published videos of Little's interviews to officers in prison.