Last year, Samuel Little confessed to strangling 93 women between 1970 and 2005.
From his prison cell in California, where he is serving three life sentences for three murders in the 1980s, he has started to paint portraits of his victims.
Law enforcement officers have used these paintings to try to identify some of Little's crimes they haven't been able to place.
America's most prolific serial killer, Samuel Little, has been helping law enforcement identify all of his victims by painting their portraits.
The 79-year-old went largely unknown until 2014, when DNA evidence connected him to the murders of three women in California, where he's now serving three life sentences.
Last year, Texas Ranger James Holland flew out to California to interview Little in prison, suspecting he might be connected to the 1994 murder of a sex worker in Odessa, Texas, according to "60 Minutes."
Federal Bureau of Investigation
Not only did Little confess to that crime, but he eventually copped to a total of 93 murders between 1970 and 2005, 50 of which the FBI has confirmed so far.
The agency says it has struggled to confirm all 93. Little's memories of the crimes are fading, and the women he targeted were often sex workers or drug addicts whose deaths were either misreported as drug overdoses or accidents, or whose bodies were never found in the first place.
So when Holland learned that Little had an artistic flair, he provided him with art supplies and encouraged him to draw his victims. Law enforcement officers have since been using these portraits to try and identify the rest of the victims. Many of these drawings are available on the FBI's website, along with other information that Little has provided about the crime.
Anyone who has information on these women is asked to call the FBI at 1-800-call-FBI. Tips can also be submitted online at tips.fbi.gov.