Sokolov's lawyer told the TASS news agency that Sokolov had confessed to the murder.

Sokolov told investigators that he shot Yeshchenko in a fit of rage on Thursday, then entertained guests on Friday while her body lay behind a closed door.

After the visitors had left, he dismembered and disposed of the remains. He told police the task made him physically ill, and he drank heavily to keep himself at it. He might have jumped into the Moika, which is shallow enough to stand in, when the backpack didn't sink, or he might have been so drunk that he toppled in accidentally. Both versions have been reported. In any case, he called out in anguish, and a passing taxi driver called the police.

His plan, local news organisations reported, was to make his way – dressed as Napoleon – to the Peter and Paul Fortress and take his life in front of tourists.

Locals say Yeshchenko lived with Sokolov for some time but had recently moved out. Photos online show them dancing, she in an Empire-style dress with white gloves up past her elbows, he in a glittering uniform decked with gold braid and a red sash. He called her Isabelle, after one of the Bonapartes, and insisted she call him Sire. They co-authored two scholarly articles.