A Russian economist who has criticized President Vladimir Putin's policies says he was forced to leave Russia after worrying he could lose his freedom on "very bogus grounds."

Sergei Guriev told the AP on Friday that he wanted to escape pressure from a new criminal investigation around jailed oligarch Mikhail Khodorkovsky, once Russia's richest man.

In his first interview since taking a one-way flight to Paris on April 30, Guriev said he feared he could share the fate of witnesses in two previous investigations into Khodorkovsky who were later charged and died in prison.

"I don't see under what circumstances I can return," he said. Investigators repeatedly told him he was fair game, he added.

Guriev ran Moscow's New Economic School from 2005 prior to leaving.