A man who has admitted killing more than 90 people, including one from Texas, may be one of the most prolific serial killers in U.S. history if convicted, officials say.

Samuel Little

Samuel Little, 78, made the confessions in a series of interviews with federal authorities and law enforcement from 14 states. Investigators have tied him to about 30 of the crimes so far, but don't doubt the confessions, The New York Times reported.

In May, Texas Ranger James Holland traveled to California where Little was serving three consecutive life sentences for the murders of three women in the 1980s.

During the interview, Little admitted to killing Denise Christie Brothers in Odessa in 1994 and gave details that were never released to the public, officials said. Brothers, 38, was found strangled about a month after her disappearance.

A grand jury indicted Little in July in Brothers' killing. On Monday, he appeared in court in Ector County for a pre-trial hearing, the Odessa American reported.

Holland was able to use the case "as a catalyst to continue to gain trust and information from Little in order to solve dozens of other cases," Ector County District Attorney Bobby Bland said in a written statement.

"Due to the dedicated and tireless work of Ranger Holland and the Texas Rangers, Little will be confirmed as one of, if not the most, prolific serial killers in U.S. history," Bland said.

Gary Ridgway, who became known as the Green River killer, was convicted of 49 murders in Washington State during the 1980s and 1990s, the highest number of murder convictions for an American, the Times reported.

Little, who has heart disease and diabetes and uses a wheelchair, has been held in the Ector County jail since October when he was transferred from Wise County, where he was being interviewed.

Investigators have said Little may be talking because he prefers the Texas jail to the environment at the Los Angeles prison where he was serving time. He also appears to enjoy the attention he is getting when he speaks about details only he would know, the Times reported.

Little has been interviewed by authorities from Texas, Florida, Georgia, Kentucky, Tennessee, Mississippi, Louisiana, Illinois, Ohio, California, Indiana, Arizona, New Mexico, South Carolina, the Federal Bureau of Investigation and the U.S. Justice Department.

"As a result of this investigation, not only did the family of Denise Brothers get answers but so will hundreds of family members know the truth after decades of questions," Bland said.

With a confession from Little in October, authorities in Marion County, Fla., were able to close the book on the August 1982 slaying of 20-year-old Rosie Hill.

Marion County Sgt. Michael Mongeluzzo traveled to Wise County in October to interview Little who confessed to killing Hill. Her remains were found in a wooded area near a hog pen.

"It's scary the clarity he has about certain things after all this time," Mongeluzzo told the Times. "He remembers names and faces."

During the interview, Little told Mongeluzzo that God put him on this earth to kill Hill, the Marion County Sheriff's Office said in a written statement.

Authorities had tried to connect Little to Hill's slaying before. Detectives interviewed him in Mississippi, where he had been arrested in December 1982 on charges of attempted murder, aggravated assault and rape of two prostitutes. Little claimed not to know Hill and there was not enough evidence to charge him in the crime, the sheriff's office said.

Little won't be charged in Hill's murder now because of the three life sentences and indictment in the Odessa case, the sheriff's office said.

Mongeluzzo told the Times he asked Little how he avoided arrest for so long. He said Little told him, "I can go into my world and do what I want to do. ... I won't go into your world."

Little is thought to have targeted women who were poor or addicted to drugs or alcohol. Detectives said the former boxer would beat the women before strangling them, the Times reported.

He got sexual gratification from the strangulation, said Los Angeles County prosecutor Beth Silverman who won the three murder convictions against Little.

Little was arrested close to 100 times across the country on charges such as kidnapping, rape and armed robbery, but served less than 10 years in prison. He was arrested and acquitted in a 1983 Florida homicide.

The path to the three murder convictions began after DNA found on the bodies of three women killed in the late '80s matched his, the Los Angeles Times reported. Little, also known as Samuel McDowell, was tracked to a homeless shelter in Kentucky. He was convicted in September 2014 and sentenced to three consecutive life terms without the possibility of parole.