MOSCOW — Russian investigators have raided the homes of at least five people working for an exiled oligarch, in connection with a decades-old dispute over what was once the country’s largest oil producer.

In a statement, the Investigative Committee said that the Thursday morning raid relates to a 2003 criminal case involving the Yukos oil company, which was disbanded four years later after filing for bankruptcy.

Its owner and head Mikhail Khodorkovsky was sent to prison in what was largely seen as the Kremlin’s payback for his political ambitions. Khodorkovsky was pardoned after spending a decade behind bars. He continues to oppose Russian President Vladimir Putin from exile.

In footage said to be connected with the raid, Russian television showed a policeman putting a man face-down on the floor and holding his hands behind his back.

The five people whose homes were raided include the head of Khodorkovsky’s charity foundation in Russia who was in high school when the Yukos case was opened. Investigators earlier this year raided the Moscow office of the charity foundation, Open Russia which provides legal support for victims of rights abuse and runs media projects.

“Raids will not stop our work but they help to understand who the (Russian) intelligence agencies are protecting,” Khodorkovsky, who lives in exile in London, tweeted.

Russian investigators did not stop in their attempts to charge Khodorkovsky with other crimes even after he was released following a presidential pardon in December 2013 in an apparent goodwill gesture ahead of the 2014 Winter Games in Russia’s Sochi. In 2015, investigators accused the exiled tycoon of involvement in the 1998 killing of a Siberian mayor, accusations he has dismissed as sham.