Tiny is now serving a pair of lifestyles sentences in a California penal complex - the set up he has drawn coloration portraits of his victims, a range of whom had been black girls.
On Sunday, the Federal Bureau of Investigation sent out a press release saying Violent Criminal Apprehension Program (ViCAP) analysts believe all his confessions are credible, giving Little, now 79 years old, the dubious dishonour as the American record holder.
The FBI is asking for the public's help in matching the remaining unconfirmed confessions.
Samuel Little confessed to 93 murders, according to the FBI, but investigators have only been able to verify about 50 of those reported.
Little claimed to have strangled 93 people from 1970-2005, but the report on FBI.gov said that many of his victims were never found, and others may have been ruled as accidental, or overdoses, or even as undetermined causes.
Law enforcement have been able to verify 50 of Little's confessions, but that leaves dozens of victims still unnamed and yet to be found.
Some of his victims' bodies have never been found but Little himself has drawn colour portraits of 30 of the women and the Federal Bureau of Investigation are hoping their relatives or friends may be able to connect them to Little.
Little targeted vulnerable individuals, mostly black women, many of whom were sex workers or drug users, officials say.
His first interview took place in May past year, when Ranger Holland visited Little in California State Prison.
In another case, Little detailed strangling a woman in 1993 in a motel room in Las Vegas.
Little has now confessed to killing about 90 women.
Holland noted that Little liked to draw and gave him art supplies.
It also makes him more prolific than the infamous Ted Bundy, who confessed to killing more than 30 women in the 60s and 70s, before he was executed in 1989 and John Wayne Gacy, known as the Killer Clown, who also confessed to more than 30 murders, mostly young boys, before his execution in 1994.
In a 2018 prison interview with NY magazine's website The Cut, Little said he considered his victims his "babies".
He has since been extradited to Texas over a murder in the state and is expected to die in jail.
The FBI has arrange a web site displaying his videotaped recollections of unidentified killings, alongside sketches - drawn by Little - of the folks he claims to have murdered. But Samuel Little might top them all.