A group of friends slashing their dirt bikes through the woods outside Saucier, Miss., found Julia Critchfield. It was January 1978. The 36-year-old mother of four was naked, her body sprawled on a roadside. She had been strangled. Her killer had draped a black dress over her frame.

Nearly 500 miles away and four years later, Rosie Hill's body was discovered near a hog pen in Marion County, Fla. The 21-year-old was last seen four nights earlier leaving a bar with a stranger in August 1982. She also had been strangled.

Nearly 700 miles east, Melissa Thomas turned up in a church cemetery in Opelousas, La. It was January 1996. Again, strangled.

The three cases — separated by hundreds of miles and spread over three decades — each stumped local law enforcement. Eventually, the crimes slid into obscurity. The passing years chipped away at witnesses' memories. Evidence sat in storage or was misplaced or swallowed up by hurricanes. Family members mourned publicly, then sank into the private ritual of grieving for the victim of an unsolved crime.

Unbeknown to anyone, there was an invisible thread running through each murder — and possibly many more. Authorities learned about the link only this summer, when a 78-year-old serial killer began talking in his Texas jail cell.

In September 2014, Samuel Little was convicted in Los Angeles of the cold-case murders of three women between 1987 and 1989. DNA evidence linked Little — also known as Samuel McDowell — to the slayings. He was given three life sentences, the Los Angeles Times reported at the time.

But last summer, Little's DNA also connected him to the unsolved 1994 murder of an Odessa, Texas, woman named Denise Christie Brothers — another young woman strangled and dumped. In July, Little was indicted on a charge in that crime, and transferred to Texas. According to a release from the Ector County District Attorney's Office, a Texas Ranger named James Holland struck up a rapport with Little, and the elderly man began talking.

"People for years have been trying to get a confession out of him and James Holland is the one who finally got him to give that information," Bobby Bland, the Ector County district attorney, told the Associated Press.

His words delivered a shock. Little claimed he was responsible for more than 90 murders nationwide between 1970 and 2013.

Since Little's confession, he has already been linked to 30 unsolved crimes. Authorities have confirmed his role in at least nine cases, including Critchfield, Hill and Thomas. Right now, law enforcement officials from across the country continue to trek to his jail cell, hauling along their open case files, hoping the convicted killer can offer answers.

Little's 90 murders would rank him among the most deadly American killers. Ted Bundy is suspected of killing at least 30 victims. Randy Kraft, who claimed he killed as many as 65 people, was convicted in 1989 of 16 deaths. Convicted of 49 murders, Gary Ridgway, the "Green River Killer," is thought to be the country's most prolific serial killer.

"If all of these are confirmed, I mean, he'll be the most prolific serial killer, with confirmed killings, in American history," Bland said.