Eighteen months ago, a Texas Ranger traveled to a California State Prison to ask convicted murderer Samuel Little about a cold case.
Denise Brothers was a prostitute who went missing in 1994 in Odessa, Texas. Little confessed to murdering her and his confessions didn't stop there.
Little, 79, has now admitted to killing 93 people, including a Houston woman. Last year, Little told an HPD cold case investigator he killed an African-American female prostitute in her early 20s either between 1976 to 1979 or as late as 1993.
"We still have yet to identify her, so she is a Jane Doe at this point," said Sgt. Richard Rodriguez, regarding the investigation in November 2018.
Little has now confessed to 93 murders between 1970 and 2005.
The FBI announced Sunday Little is the most prolific serial killer in U.S. history. He has killed more people than Ted Bundy and John Wayne Gacy combined.
Ted Bundy confessed to 30 homicides from about 1974 to 1978. John Wayne Gacy killed at least 33 boys and young men in the 1970s.
Little says he killed in more than 15 states, mostly in California and Florida.
More than 50 of his confessions have been verified, with several more pending. Investigators believe "all of his confessions are credible."
Now the FBI needs help identifying the rest of his victims. The agency released five sketches of unknown women, drawn by Little himself.
"For many years, Samuel Little believed he would not be caught because he thought no one was accounting for his victims," said ViCAP Crime Analyst Christie Palazzolo. "Even though he is already in prison, the FBI believes it is important to seek justice for each victim to close every case possible."
Little has been convicted of at least eight murders and is serving several life sentences in a California prison.
Little, who also went by the name Samuel McDowell, targeted vulnerable women who were often involved in prostitution and addicted to drugs, authorities have said.
Little strangled most of his victims. Their deaths were originally ruled overdoses or attributed to accidental or undetermined causes. Some bodies were never found. Once a competitive boxer, Little usually stunned or knocked out his victims with powerful punches before he strangled them while masturbating.
If you have any information linked to Little's confessions, please contact the FBI at 1-800-CALL-FBI or submit a tip online at tips.fbi.gov.
To see Little's sketches and to read detailed descriptions of the unnamed women he's confessed to killing and the stories about how he met them, visit the FBI's website.
RELATED: FBI releases sketches that serial killer Samuel Little drew of his murder victims