The FBI has named convicted murderer Samuel Little as the most prolific serial killer in US history.

The 73-year-old is serving time for the murders of three women but has now confessed to a total of 93 – of which 50 killings have been conclusively linked to him by US authorities.

Although Little’s other alleged murders have yet to be confirmed, the FBI believes all of his confessions are credible, The Independent reports.

The FBI says the lifelong drifter targeted “marginalised and vulnerable women who were often involved in prostitution and addicted to drugs”.

“For many years, Samuel Little believed he would not be caught because he thought no one was accounting for his victims,” said FBI crime analyst Christie Palazzolo. “Even though he is already in prison, the FBI believes it is important to seek justice for each victim – to close every case possible.”

Little strangled his victims in a killing spree that stretched from 1970 to 2005. However, many of the murders went undetected because his victims’ deaths were ruled overdoses or attributed to “accidental or undetermined causes”, says the investigative agency’s website. Some of his victims’ bodies have never been found.

Little had been a known criminal since his teenage years, with convictions for shoplifting, fraud, drug charges, solicitation, and breaking and entering. He dropped out of high-school in Ohio before embarking on a nomadic lifestyle.

“He would shoplift and steal in a city or town to gather the money to buy alcohol and drugs, but never stayed in one place for long,” says the FBI.

In the early 1980s, he was charged with the murders of multiple women in Mississippi and Florida, but “with limited ability to analyse DNA evidence, officials were unable to prosecute him”, says the Independent.

It wasn’t until 2014 that he was convicted and sentenced to three consecutive life sentences with no possibility of parole for the murders of three Los Angeles women. – theweek.co.uk