Ruslan Krasnov was an assassin hired by Joshua Vikner to kill Sherlock Holmes' father Morland in 2014 but failed in the attempt, wounding Morland and killing his lover Sabine. He is Chechen and is missing his left thumb.
In 2016, after Morland provides Sherlock with access to Sabine's emails, he discovers a worm which blind copied her emails and sent it to Ruslan. Holmes tells Morland that Ruslan is serving a life sentence in a super max prison outside of St. Petersburg, Russia. ("Who Is That Masked Man?") Several weeks later, Sherlock tells Joan Watson that Krasnov escaped from prison. Watson discusses this with Morland who already knew and denied breaking him out of prison. ("You've Got Me, Who's Got You?") Watson blackmails one of Morland's employees Emil Kurtz to provide info from Morland's organization and discovers that Morland paid off officials in Novgorod to find Krasnov. ("Ain't Nothing Like the Real Thing") Watson reveals to Sherlock the info her mole has provided and that Morland hasn't been telling them about his actions with regards to Krasnov. Morland requested a ring that was stored at The Brownstone from Sherlock which he believes is payment for finding out Krasnov's whereabouts. ("Turn It Upside Down")
|Krasnov is seen disguised as a water jug delivery man and enters Morland's offices at night just after Morland leaves for the day. He kills a security guard and one Morland's VPs, Allison Pitzker, before planting a bomb that looks like water jugs. He exits the building and remotely detonates the bomb. Morland informs Sherlock that he had Krasnov's left thumb in a jar which he cut off to escape from prison. Sherlock deduces that Krasnov can be found by a dolly he bought to transport the jugs. Ruslan is picked up by the police and during interrogation, claims to not speak English. After Holmes is able to demonstrate he can speak Russian, Ruslan says they have no evidence he's committed a crime in the US and there is no extradiction treaty for the crimes he committed in Russia.
|Sherlock meets with Vikner who says that Krasnov may talk if he's forced to serve time in the US. The police discovers that Ruslan killed a security guard at a chemical facility as they find a bloody hand print at the scene. As Krasnov is being escorted by two detectives at the 11th precinct, an officer from the 87th precinct asks if the man they are escorting is Krasnov. When they confirm it is, the officer shoots Krasnov, killing him, and then kills himself. Sherlock asserts the killing happened to prevent Krasnov from saying who hired him to carry out the murder attempts on Morland. ("The Invisible Hand")