A Russian former policeman was convicted on Monday of killing 55 women and one man, bringing the total number of women he is convicted of killing to 77, a court said.

Mikhail Popkov predominantly targeted women aged 18 to 50 in urban areas in the eastern Siberian region of Irkutsk from 1992 to 2007, the Irkutsk-based court said in a statement.

He would meet them casually and flirt with them, the statement said. "The victims ended up outside of the city ... in a forest, cemeteries, roadsides."

Many of the victims were residents of the cities of Irkutsk and Angarsk, and the town of Usolye-Sibirskoye, the statement said.

Known as the "Angarsk maniac," his victims included a fellow policeman, Russia's federal investigative agency said.

It took law enforcement officers rather thorough work analysing unsolved crimes to link Popkov to them, including questioning more than a thousand potential witnesses, the Investigative Committee said in a statement.

As a police officer, Popkov would have had knowledge of forensic practices. Russian media has reported that many of his victims were mutilated.

"The identities of 17 of his victims have not been determined," the court said in its statement.

While tabloids have reported that Popkov targeted inebriated woman and prostitutes, the Investigative Committee said his victims were "women of various social status and position in society."

Russian state news agency RIA Novosti reported that Popkov was motivated by his wife supposedly being unfaithful.

Popkov was initially convicted three years ago for the murders of 22 women and sentenced to life in prison. He has been stripped of his rank of junior lieutenant.