The two serial killers with a higher victim count are both South American. Luis Garavito, who killed 138, and Pedro Lopez, who killed 110.
His modus operandi was to sexually assault the victims before he unleashed on them any sharp weapon he could - be it a knife, tool or even an axe.
He wore his police uniform as he lured drunken victims into his police car, offering them late night rides back home from bars.
The brutal Werewolf stalked his prey for almost 20 years before he was eventually captured.
His wife Elena, 51, and daughter Ekaterina, 29, a schoolteacher, supported him through his early court proceedings and refused to believe he was a mass killer.
They have since distanced themselves from him.
A Russian police spokesman made the grim announcement that cleared up any confusion over the number of victims.
"To clarify the numbers, Popkov has confessed to 59 new murders," said Lieutenant Karina Golovacheva, of the Russian Investigative Committee in the region of Irkutsk region.
The Russian Investigative Committee is Moscow's version of the FBI.
"We are not counting in this total those 22 for which he was already sentenced. These cases are already closed.
"So there are 59 new murders. That means, if we add them to the earlier 22, it will be 81 murders in total."
Lt Golovacheva added The Werewolf had now been charged with murder for 47 of the additional 59 cases. Further charges were likely.
"When the investigation is finished, and Popkov has read the case materials, the trial can begin," she told The Siberian Times.
During his latest court appearance The Werewolf was asked by judge Pavel Rukavishnikov how many women he had actually killed.
He answered matter-of-factly: "I can't say exactly, I didn't keep a record."
He then went on to tell the court" "I admit my guilt in full ... committing the murders, I was guided by my inner convictions."
After his initial arrest, he told police he wanted to rid the streets of prostitutes.
