Samuel Little, 78, is locked up in Texas for a 1994 murder of a woman. He was extradited from California, where he was serving three life sentences for killing three women there.
He recently confessed to murdering 90 women over three decades across the country and so far, investigators have been able to match 30 cases.
Sources confirm that he confessed to picking up a woman in Memphis, killing her and then dumping her body in the Mississippi River on the Arkansas side.
MPD's homicide bureau confirmed they are looking into this, but no victim has been identified at this point.
Another woman he confessed to killing has family here in Memphis. WREG will have an interview with that family Monday.
Investigators say Little would prey on troubled women, targeting drug addicts and prostitutes. Some he found at clubs or bars.
They say he would strangle his victims, dump their bodies and leave town.
If Little's confession turns out to be true, he will become the worst serial killer in the history of the United States.