Former intelligence colonel Vladimir Kvachkov, cleared Wednesday of involvement in a high-profile assassination attempt, is back in detention after being held on suspicion of preparing a violent overthrow of the government, Interfax reported.

Law enforcement officers also searched Kvachkov's apartment before detaining him, his lawyer Alexei Pershin told the news agency.

Investigators did not comment on the case. Kvachkov told Gazeta.ru that he had barricaded himself in his apartment and attempted to prevent Federal Security Service officers from entering.

Kvachkov was earlier questioned by the FSB for calls to overthrow the government allegedly made by a member of the Minin and Pozharsky's Public Militia group, which he heads, Interfax reported, citing Kommersant.

An outspoken ultranationalist, Kvachkov was charged with leading a shooting and bombing attack in 2005 on a convoy carrying Rusnano chief Anatoly Chubais, who at the time was head of national power monopoly Unified Energy System.

Chubais, an architect of the liberal reforms in the 1990s, is reviled by many for the chaos that accompanied the country's rapid transition to a market economy.

A jury cleared Kvachkov, former paratroopers Robert Yashin and Alexander Naidenov, and nationalist writer Ivan Mironov in 2008. The Supreme Court overturned the decision in 2009 and a retrial ended with another acquittal in September, upheld by the Supreme Court on Wednesday.

A new investigation has been opened into the attack on Chubais, the Prosecutor General’s Office said Wednesday.