MOSCOW: In an unexpected renewal of a feud between the Kremlin and Russia's former richest man, exiled tycoon and ex-prisoner Mikhail Khodorkovsky was summoned for questioning in Moscow on Tuesday.

Khodorkovsky posted on social media a copy of the summons, which was delivered to the Moscow home of his 82-year-old father, who was himself questioned by investigators in August about the 1998 killing of a Siberian mayor.

Investigators announced in June that they were reopening the probe into the slaying of Vladimir Petukhov and considered Khodorkovsky a prime suspect. Khodorkovsky and his associates have denied involvement in the killing in Nefteyugansk, the town where his company, Yukos, was headquartered at the time.

Khodorkovsky on his personal Twitter account described the summons as a "feeble attempt to change the subject" in a reference to a recent anti-corruption investigation which pointed at top Russian prosecutors.

The tycoon's spokeswoman, Olga Pispanen said that Khodorkovsky "has no intention to get in touch with investigators" because "he had played in this farce for 10 years."

Khodorkovsky, 52, spent 10 years in prison on charges of tax evasion and embezzlement, which have been seen as punishment for challenging President Vladimir Putin's power. Since his 2013 release, Khodorkovsky has continued to oppose the Kremlin from exile in Switzerland.

While Khodorkovsky was in prison, Putin and other senior officials kept dropping hints about his possible involvement in Petukhov's murder. In 2010, Putin went as far as to suggest that Khodorkovsky had "blood on his hands."

Khodorkovsky walked free in December 2013, less than two months before the start of the 2014 Winter Games in Sochi and just a few months before his scheduled release, after Putin issued a presidential pardon in response to Khodorkovsky's petition to leave the country to meet his mother who was undergoing medical treatment in Germany. Khodorkovsky was put on the plane on the day of his release. He has not returned to Russia since.

Putin's spokesman Dmitry Peskov told reporters on Tuesday that Putin had some "suspicions and information" about Khodorkovsky's possible involvement in Petukhov's murder when he issued the pardon but that the reports were not conclusive

Putin "did not have the information that has now surfaced and triggered the actions that investigators are taking," he said.

In exile, Khodorkovsky has been supporting opposition politicians, independent media and political prisoners in Russia. He has been an outspoken critic of Moscow's annexation of Crimea and involvement in a military conflict in eastern Ukraine.

The pre-Olympics release of Khodorkovsky and two women of the Pussy Riot collective was viewed as a goodwill gesture at the time, showing that the Kremlin was willing to forget old grudges.