Strelkov’s lawyer, Alexander Molokhov, said that after he had been detained his flat had been searched.
The BBC reported Girkin, 53, later appeared at Meshchansky district court in the north-east of the capital, where the judge rejected his request for the hearing to be held behind closed doors. He will now remain in pre-trial detention until at least September 18.
It follows an abortive mutiny last month led by another outspoken Krelim critic, Yevgeny Prigozhin, boss of the Wagner mercenary force, who is still free but has sharply curtailed his own verbal attacks.
In a post earlier this week, the former Federal Security Service officer changed from criticising Putin’s military decisions to turning to the issue of his leadership of the country in general. He called Putin a “useless coward” and said the country could not survive another presidential term.
“For 23 years, a non-entity was at the head of the country, who managed to ‘pull the wool over the eyes’ of a significant part of the population,” Girkin wrote. Now he “is the last island of legitimacy and stability of the state”.
“The country will not survive another six years of power of this useless coward. The only useful thing he could do ‘before the curtain falls’ … is to ensure a transfer of power to someone truly capable and responsible.“
A criminal court last year in the Netherlands found that Girkin, who was a commander of the Kremlin-backed separatist forces, had helped supply the missile system used to shoot down MH17 on July 17, 2014.
The Boeing 777 commercial jet was shot over eastern Ukraine, killing 15 crew members and 283 passengers belonging to 17 nationalities.
Girkin had previously said he felt “a moral responsibility” for the deaths of the 298 people onboard the plane, but refused to admit to downing the passenger jet.
Girkin, Sergei Dubinsky and pro-Moscow Ukrainian Leonid Kharchenko were tried in absentia – a criminal proceeding when the defendant is not present in the court – since they were still at large.
In May, he announced he and others had set up the “Club of Angry Patriots”, to enter politics to save Russia from what he said was the danger of turmoil due to military failures in Ukraine.
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