Samuel Little forgot the names of the 93 women he killed. So he drew pictures of them.

Samuel Little is officially the worst serial killer in US history. He’s confessed to murdering 93 women between 1970 and 2005. That’s three times as many as Ted Bundy. This week, the FBI put out a statement saying that Little’s confessions are “credible”.

So who is he, and how did he get away with killing so many women over such a long period?

Little is now 79 and confined to a wheelchair. But when he was younger, he was a boxer. Detectives have described him as a “charismatic psychopath”.

His mother was, as he puts it, “a lady of the night”. He was born in Georgia, possibly in jail, and he was raised mostly by one of his grandmothers in Ohio. By the time he was 16, he was already in trouble with the law, being sent to juvenile detention for breaking and entering.

As an adult, Little drifted from state to state. He was arrested for a range of crimes, including armed robbery, rape and aggravated assault on a police officer. For some reason, he never spent long in jail.

“It’s the craziest rap sheet I’ve ever seen,” Los Angeles deputy district attorney Beth Silverman told the Star Advertiser. “He’s gotten break after break after break.”

In 1976, Pamela Kay Smith was found crying for help outside a house in Sunset Hills, Missouri. She was naked from the waist down and her hands were tied behind her back. She told police that Little had picked her up in his car, beaten her and raped her.

Police found Little nearby, still in his car. He admitted to beating Smith, but said he hadn’t raped her. He was sentenced to just three months in jail.

It’s believed the short sentence may have been due to Smith being a heroin addict.

Six years later, a young woman called Melinda LaPree disappeared in Pascagoula, Mississippi. Her remains were found a month later. She had been working as a prostitute, and witnesses had seen her getting into a car with a man who looked like Little.

Little was arrested for her murder and the assault of two other prostitutes. But he was never charged, partly due to victims and witnesses being prostitutes and not seen as credible.

In 1984, Little was charged with the attempted murder of two prostitutes in San Diego, California. He ended up serving just two and a half years in jail.

As he drifted from state to state, Little would deliberately choose victims who he thought he could get away with killing, including prostitutes and drug addicts. These women sometimes weren’t reported missing for weeks, and police were less likely to put effort into solving their disappearances.

Little would beat his victims brutally, using his boxing skills. He punched one woman so hard in the stomach that he broke her spine. Then he would strangle them. But he rarely raped them.

“The way he gets sexual gratification is during the strangulation,” Silverman told The New York Times.

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In the end, it was a minor drug offence that did Little in. In 2012, he was arrested for possession of a crack pipe at a homeless shelter in Kentucky. His DNA linked him to the murders of three young women in Los Angeles in 1989. Each of those women had been punched unconscious and strangled.

Detectives started looking into his past, and found that a huge number of unsolved murders had taken place in towns where Little happened to be living at the time.

"It's just statistically impossible for a man to keep being in a town where a body turns up," Mississippi detective Darren Versiga said.

Little was jailed for life for the three LA stranglings. But he refused to admit to any of the other murders he was suspected of.

Then, in 2017, a Texas ranger called James Holland, who had a reputation as a serial killer whisperer, started visiting Little. Holland and Little bonded, calling each other Jimmy and Sammy. Before long, Little began opening up. He said his first victim was a woman with strawberry-blonde hair, who he’d murdered in 1970 in Miami, Florida.

“It was like drugs,” he told Holland. “I came to like it.”

Little eventually confessed 93 killings to Holland. The problem was that he was terrible with dates – sometimes not being sure which decade the murder had taken place – and not great with names. But Holland realised Little had an incredible memory for faces. He organised to have an art studio set up in Little’s cell. There, he began doing portraits, in watercolour, acrylic and chalk, of the women he’d strangled.

Earlier this year, the FBI posted some of those portraits on its website. Already, they’ve begun helping with the identification of victims. More recently, the FBI has posted footage of Little talking to Holland about his victims.

Little’s memory is failing and so is his health. He has diabetes and heart problems. The race is on to identify as many of his victims as possible before he dies.

“Samuel Little has given me a massive gift, a gift to bring closure to victims’ families who have gone years without knowing what really happened to their loved ones,” Holland told the Los Angeles Times. “I have to run with this and take it wherever it goes, do whatever it takes. And we know time is slipping away.”