A well-known Russian military historian and professor at St. Petersburg State University was found in a river in the center of the city early Saturday morning drunkenly trying to dispose of a woman’s severed arms, according to Russian media reports.

Police reportedly soon found the woman’s decapitated head and body, along with a bloody saw, in his apartment, and divers are said to have found her legs in black plastic bags at the bottom of the Moyka River.

The alleged historian-turned-murderer, identified by Russia’s Interfax news agency as 63-year-old Oleg Sokolov, has already confessed to the killing, according to his lawyer, Alexander Pochuyev.

“If such a heinous crime, which my client has confessed to, did take place, it was committed under the influence of strong factors, possibly pathological intoxication or temporary insanity,” Pochuyev was quoted as saying by Radio Free Europe/Radio Liberty.

Pochuyev added “the verdict has not been passed yet, and until that moment a person is forbidden to be considered guilty” under Russia’s Criminal Code.

Sokolov has reportedly entered a plea bargain for the gruesome murder of the 24-year-old victim, tentatively identified by law enforcement sources as Anastasia Eshchenko, one of his students and his co-author on research projects about the French military rule of Napoleon Bonaparte.

Police have not yet confirmed a motive, but several local media reports suggest Sokolov and Eshchenko had a closer relationship than that of a teacher and student. Interfax cited sources saying the two lived together.

Sokolov is said to have told detectives during his interrogation that he purchased a saw to get rid of Eshchenko’s body and drank booze during the dismemberment because he “repeatedly felt sick.” He also reportedly said he planned to commit suicide afterwards wearing the uniform of Napoleon.

Sokolov is considered one of Russia’s leading experts on Napoleonic wars, and is well-known for reenacting moments of Napoleonic history. He was awarded France’s Legion d’Honneur in 2003.

Sokolov was also a member of France's Institute of Social Science, Economics and Politics, but he had been stripped of his position on its scientific committee Saturday, the society said in a statement.

“We could never imagine that he could commit such an odious act,” as an academic of such high standing, the ISSEP said. The battle re-enactor was also initially listed as a member of the Russian Military Historical Society, but by Saturday evening the organization insisted it had no ties to him.

Russian state media reports that Sokolov is detained in a hospital and is being treated for hypothermia.