America's worst serial killer Samuel Little's disturbing TV interview

Samuel Little has confessed to 93 murders across America between 1970 and 2013. Photo / 60 Minutes

WARNING: Distressing content

America's most prolific serial killer recently confessed for the first time about almost 100 murders he committed over decades.

And once he started talking about his crimes, he never really stopped, news.com.au reports.

Now he even openly laughs about how some of his victims looked while he was killing them.

Samuel Little, 79, is considered the deadliest serial killer in America's history, having confessed to 93 murders across the country between 1970 and 2013.

That's more than committed by Ted Bundy and Jeffrey Dahmer combined.

So far, investigators say they have established Little's ties to dozens of murders — and they have little reason to doubt his remaining confessions.

In a police interview with Texas ranger James Holland, which aired on 60 Minutes in America overnight, Little recalled strangling a "real friendly … little, skinny, black girl" to death in North Little Rock, Arkansas. He claimed the victim was "laughing while I was killing her".

An interview with Samuel Little aired on 60 Minutes in America overnight. Photo / 60 Minutes

"[She] had buck teeth. Had a gap between her teeth, that's what it was," Little said as his face broke into a wide smile and gave way to a chuckle.

"You know that she's fighting for her life, and I'm fighting for my pleasure."

Little and his killing spree went undetected for nearly half a century. That was until Holland developed a hunch about Little's guilt, struck up a rapport with him, and coaxed him into confessions that enabled investigators across the country to solve more than 50 cold cases.

"Nothing he's ever said has been proven to be wrong or false," Holland said.

"We've been able to prove up almost everything he said."

In one police interview, Little told Holland how he "got away with numerous murders, of women, in my life over the span of 50 years".

Convicted in 2014 for the murder of three women in Los Angeles in the 1980s, Little was already serving time when his DNA was also linked to the 1994 unsolved murder of Texas woman Denise Christie Brothers.

In July last year, Little was charged with Brothers' murder and extradited from California to Texas.

Some of Samuel Little's many victims.

He initially pleaded his innocence. Then he met Holland.

The killer went on to reveal how he killed "the most" in the states of Florida and California.

Holland told 60 Minutes he developed a strategy for effectively interviewing Little that included steering clear of some topics "that normally work for investigators".

"You avoid things like remorse and closure for the family," he said.

"It doesn't appeal to [serial killers] at all.

"I mean, you're asking them to open up their soul to the things that are more intimate to them than anything in life.

"Why should they do that with you?

"And that's what you're workin' for."

Holland told the programme he became familiar with how Little would respond when asked to recall the murders he committed.

"With Sammy, there's indications of visualisation, of when he's thinking about a crime scene," Holland said.

Investigators say they have established Samuel Little's ties to dozens of murders. Photo / AP

"He'll start stroking his face. And as he's starting to picture a victim, you'll see him look out and up.

"And you can tell he has this revolving carousel of victims, and it's just spinning, and he's waiting for it to stop at the one that he wants to talk about."

These days, Little is frail and wheelchair-bound, his body ravaged by diabetes and heart disease.

He spends most of his time recounting in comprehensive detail how he committed the murders — the faces, the places, where he picked up vulnerable women from bars and streets and where he left their strangled bodies.

Many of the murders Little confessed to bear striking similarities to those of Carol Alford, 41, Audrey Nelson, 35, and Guadalupe Apodaca, 46 — the three women he was originally convicted of killing and sentenced to three terms of life with no parole.

Little bashed, strangled and masturbated over his victims before dumping their bodies in alleyways and abandoned garages.

His latest confessions enabled investigators to close previously unsolved murders in the states of Georgia and Louisiana after he provided details "that only the murderer would have known", according to an internal Louisiana State Police memo.

Samuel Little openly laughed about how some of his victims looked while he was killing them. Photo / 60 Minutes

In Macon, Georgia, the Bibb County Sheriff's Office said in a statement that Little's confessions led to the closure of two murder cases, one from 1977 and another from 1982.

In the 1982 case, the body of Fredonia Smith was found in the backyard of a Macon home. She had been strangled.

The 1977 victim has never been identified. Her skeletal remains were found at the edge of bushland in a local backyard.

Two Bibb County investigators travelled to Decatur, Texas, to question Little. The sheriff's office says he gave them specific details and information" linking him to both slayings, and Smith's family was notified about the new developments.

Among the Louisiana victims were Dorothy Richard, 59, who was found dead in 1982, and Daisy McGuire, 40, whose body was discovered in 1996. Both had been strangled.

Little also confessed to the killing of Julia Critchfield, who was strangled and thrown off a cliff and into a dirt pit on the north end of Saucier in 1978, Rosie Hill in Marion County, Florida in 1982, and Melissa Thomas — whose body was found in a cemetery in Opelousas, Louisana, in 1996.

All three cases had baffled police and cold case detectives who would regularly try to unearth new information that always proved fruitless.

Prosecutors previously said Little preyed on vulnerable women — those who worked as prostitutes or used drugs and were most likely to go unnoticed or ignored by police.

Investigations into the other murders Little confessed to are continuing.