Russian authorities yesterday sent former billionaire Sergei Polonsky to a psychiatric institution with a notorious Soviet past to determine whether the recently repatriated fugitive requires “compulsory” psychological care, the Russian government has announced.

“Today, Mr. Polonsky was sent to an outpatient psychological/psychiatric complex [for a] juridical examination of his sanity, as well as the presence of any affectations requiring compulsory medical treatment. This examination will be conducted by the Serbsky Centre of Psychiatry and Addiction,” said the announcement from Russian Ministry of Internal Affairs spokesperson Elena Alekseeva, which was posted on the ministry’s website.

The statement did not elaborate further.

The Serbsky – or Serbski – Centre was best known during the Soviet era as a holding pen for political dissidents, who were often branded insane by the state for their allegedly schizophrenic “reformist delusions”.

According to Tanya Lokshina, Russia program director at Human Rights Watch, it “has been infamous since Soviet times for its punitive psychiatry practices”. However, she added, that chapter “is history”. “On the other hand, Serbski Institute has the authority to conduct psychiatric assessment in criminal cases. So, there is nothing extraordinary that they got involved in Polonsky’s case,” she said.

Nonetheless, in recent years, news reports of activists being detained in Russian psychiatric facilities – such as Marina Trutko in 2006, and Mikhail Kosenko in 2012 – have raised questions of a return to Soviet-style politically motivated psychiatric treatment.

Polonsky spokesman Ilya Rosenfeld yesterday brushed off the legitimacy of the decision to imprison the former businessman, sardonically joking that the detention in Serbsky – which also deals with addiction – would at least “shut up all those who spread filth about his use of drugs and alcohol”.

Meanwhile, police in Preah Sihanouk province, where Polonsky eluded Russian embezzlement charges for years, searched the eccentric former real estate tycoon’s private island in order to catalogue his possessions, Deputy Provincial Governor Chhin Seng Nguon said.

“We arrived on the island and saw 25 bungalow houses, which were just newly built in late 2014. They were built illegally on Koh Damlong,” he said. “Bronze statues like Apsaras, for displaying in the bungalows, were also kept there. We only checked his property to record it and report it to high-level authorities.”

Naval patrols, he added, would make sure the property is safe.

ADDITIONAL REPORTING BY STUART WHITE