Russian history professor Oleg Sokolov admits to butchering his student lover

Anastasia Yeshchenko and Oleg Sokolov both liked French history and enjoyed wearing period costumes. Photo / Supplied

A Russian academic has confessed to killing his student lover after he was caught drunkenly attempting to dump her severed arms in a river in St Petersburg.

Oleg Sokolov, a 63-year-old history lecturer and prominent Napoleon expert, was arrested on Saturday after he was pulled from the Moika River with a backpack containing a woman's arm.

"He has admitted his guilt," Alexander Pochuev, Mr Sokolov's lawyer, said yesterday (Sunday), adding that he regretted what he had done and was now co-operating. Mr Sokolov was reportedly drunk and fell in the river as he tried to dispose of the body parts.

He reportedly planned to commit suicide at the Peter and Paul Fortress, one of the former imperial capital's landmarks, while dressed as Napoleon.

Oleg Sokolov is a history professor at St. Petersburg State University. Photo / AP

His victim, 24-year-old Anastasia Yeshchenko, had co-authored several books with the academic and the pair had begun a romantic relationship.

They both liked French history and enjoyed wearing period costumes.

Mr Sokolov taught history at St Petersburg State University, President Vladimir Putin's alma mater, and was once close to the Russian authorities.

24-year-old Anastasia Yeshchenko. Photo / Social Media

He told investigators that he shot and killed Ms Yeshchenko during an argument and then sawed off her head, arms and legs.

"He is an elderly person," said the academic's lawyer, who went on to suggest that Mr Sokolov, who is being treated for hypothermia in hospital, was mentally disturbed.

The professor was arrested on Saturday after he was pulled from the Moika River with a backpack containing a woman's arms. Photo / AP

Police discovered the decapitated body of Ms Yeshchenko in Mr Sokolov's home along with a bloodstained saw.

Students described Mr Sokolov as a "freak" who called his lover "Josephine". Fyodor Danilov, a former student, said Mr Sokolov was regarded as one of the best lecturers, but also an eccentric who at times yelled in French.