A Russian serial killer known as "the werewolf" killed as many as 81 women, according to police.
Former Siberian policeman Mikhail Popkov, who is serving a life sentence for murdering 22 women, has confessed to 59 new killings, according to the Russian Investigative Committee (RIC).
The RIC, Russia's equivalent of the FBI, says Popkov told them he had killed the women during a rampage which ran from 1994 to 2000.
The women, aged between 17 and 38, were raped before being killed with axes, knives or screwdrivers.
The new death toll would make Popkov Russia's worst serial killer, with more victims than Andrei Chikatilo - the "Butcher of Rostov" - who murdered 53 people, and "Chessboard Killer" Alexander Pichushkin, who killed 49.
RIC spokeswoman Karina Golovacheva admitted there had been confusion over the number of victims.
"To clarify the numbers, Popkov has confessed to 59 new murders," she told the Siberian Times newspaper.
"We are not counting in this total those 22 for which he was already sentenced. These cases are already closed."
Popkov has been charged with 47 more counts of murder, and police expect to add the other 12 once investigations are completed.
He wore his police uniform as he lured drunken victims into his police car, offering them late night rides back home from bars.
The married father-of-one would then drive them to deserted areas and brutally attack them, dumping their naked bodies in the woods.
He was dubbed "the werewolf" by Russian media.
The crimes went unsolved for many years because the police failed to conduct DNA tests on their own officers.
When they finally tested the entire department, DNA found at the murder scenes was matched to Popkov.
After he was arrested in June 2012, Popkov allegedly told police he wanted to rid the streets of prostitutes.