A leading Russian military historian was arrested on suspicion of murder after he was dragged from a freezing river carrying two severed arms in a backpack.

A decapitated head and a body along with a saw covered in blood were later found at Professor Oleg Sokolov's flat in St Petersburg.

The young woman - identified by police sources as 24-year-old Anastasia Yeschenko - was a student of the professor, reported Russian media.

Professor Oleg Sokolov (right) was arrested on suspicion of murder after he was dragged from a freezing river carrying two severed arms in a backpack. The young woman - identified by police sources as 24-year-old Anastasia Yeschenko (left) - was a student of the professor, reported Russian media

A decapitated head and a body along with a saw covered in blood were later found at Sokolov's flat in St Petersburg

She had been in a relationship with the historian, 63, when he 'accidentally killed her' following an argument, according to the report which stated he had confessed to police.

Earlier reports had said the victim was a relative.

Multiple reports say the academic is in detention in hospital suffering from hypothermia.

He was dragged from the icy Moyka River in St Petersburg in the early hours of Saturday morning.

In his backpack were two female arms severed at the elbow and a gun.

The gruesome corpse and a severed head were found at his nearby apartment on Moyka Embankment, say reports.

Sokolov is considered a leading Russian expert on the Napoleonic Wars and is a professor at St Petersburg State University.

The gruesome corpse and a severed head were found at his nearby apartment on Moyka Embankment, say reports. Pictured: Search and rescue workers search the river

In Sokolov's backpack were two female arms severed at the elbow and a gun. Pictured: Search and rescue workers in the Moyka River by an apartment block where Sokolov lives

Ms Yeschenko had been in a relationship with the historian, 63, when he 'accidentally killed her' following an argument, according to the report which stated he had confessed to police

Multiple reports say the academic is in detention in hospital suffering from hypothermia

The boat used by rescue workers as they searched the icy Moyka River in St Petersburg

A rescue worker assists a scuba diver with their tank as they search the river

He is well known for reenacting moments of Napoleonic history.

Sokolov was president of the Russian Association of Military History and is now a member of the body's scientific council.

He has worked as a technical adviser to European television broadcasters on films depicting the Napoleonic era, and he was made a knight of the Legion of Honour in France in 2003.

Search and rescue workers are seen by the river. One worker wears a scuba diving tank and a ladder leans against the railings

Sokolov was president of the Russian Association of Military History and is now a member of the body's scientific council

Sokolov is considered a leading Russian expert on the Napoleonic Wars and is a professor at St Petersburg State University

Sokolov has worked as a technical adviser to European television broadcasters on films depicting the Napoleonic era, and he was made a knight of the Legion of Honour in France in 2003. Pictured: Rescue workers outside Sokolov's apartment

He was dragged from the icy Moyka River in St Petersburg in the early hours of Saturday morning (stock image)

Pictured: Moyka river embankment, where Sokolov was found with two severed arms in his backpack

Rescue workers are pictured searching the river where Sokolov was dragged out earlier this morning

A rescue vehicle is pictured outside Sokolov's flat in St Petersburg today

Two people assemble a ladder to aid their search. Sokolov was rescued from a river with two severed female arms and a gun found in his backpack

A scuba diver wearing goggles shines a torch to aid in his search of the Moyka river