Dzhokhar Tsarnaev is being sought by Russian police for questioning over a $2.7m (£1.5m) warlord-linked ransom payment to his brother’s legal team, which has sparked a major legal dispute between the two countries.
Russian prosecutors say they have arrested a man who they say is suspected of helping the Chechen leader to extort the ransom money, which is allegedly the biggest single cash payment to an opposition lawyer in Russia’s history.
Dzhohkar Tsarnaev is accused of accepting the money as payment for his brother, Ruslan Tsarni, a lawyer who was arrested in December after questioning at Moscow’s Baku airport and who has been living in hiding in the United States.
In July, Russian police released photos of Dzhogar Tsarnaev in a dark suit, wearing a red shirt with the words “Ruslan Tsarki” (Ruslan) written on it, and wearing a tie that had been pulled down around his neck.
The Russian Foreign Ministry, which was alerted to the photographs, said the photos were being circulated by the “extremists” who “have been trying to blackmail Ruslan” and threatened to release them if he did not give them “proof” that the money was paid to Tsarnid.
Russian police also allege that Dzhoyar Tsarnaev, the brothers’ younger brother, took part in the extortion plot.
In a statement on Friday, Dzhozar Tsarnaev’s lawyer said the US was “in a state of panic”, and that the family was in contact with the US embassy in Moscow.
The lawyer, Alexander Solovyov, said he was not aware of any investigation into the alleged ransom payments by Dzhochar Tsarnaev.
“We have no evidence to suggest that any of this is true,” he said.
“This is a totally fake story.”
In a separate development, a man identified only as Oleg, has been arrested in Moscow, the Investigative Committee, Russia’s federal security service, said.
Russian investigators are searching for Oleg over allegations he tried to kidnap his Russian ex-wife, Natalya Mikhaylovskaya, and extort her from her Russian boyfriend in 2011, and to kill her in a revenge plot.
She escaped with her life, but authorities believe he was killed by police.
“He tried to take revenge against Natalyal and to make her suffer in the way he wanted,” Investigative Committee spokesman Dmitry Peskov said.
The suspect is believed to have fled to the United Arab Emirates and to live there.
Oleg has been charged with kidnapping and extorting a Russian citizen, Mikhayslovs, and is being held in custody in Dubai.
Earlier this month, the International Committee of the Red Cross condemned Russia’s actions against its “vigilante” journalist, Anatoly Zakharov, who has worked for the website “Globes” for three years.
Zakhariv has been a target of Russian authorities since at least 2015, when they say he was involved in an illegal campaign to extorted millions of dollars from a Russian businessman and his wife.
In November, he was arrested by the Russian Investigative Committee.
Mr Peskov, who said Mr Zakharv was under pressure to pay a ransom for the journalist’s release, said Russia’s authorities had “completely destroyed” his career.
He added that “the international community has to do more than condemn” Russia’s treatment of Mr Zakaryov.
“It is time for Russia to come out of this state of hysteria and stop using this tactic.”
The US says Russian authorities are targeting journalists for “fear of Russian interests”.
US President Donald Trump has called Russian President Vladimir Putin a “moron” for interfering in the 2016 US presidential election.
Mr Putin has dismissed US criticism, saying Russia was “not interfering in our domestic affairs”.
“There are no reports of the US administration having any specific knowledge about this issue,” Russian Foreign Minister Sergei Lavrov said in a statement, referring to US media reports that US intelligence agencies have been monitoring Russia’s suspected involvement in the US election.