The father of Russian tycoon Mikhail Khodorkovsky has been questioned in Moscow by the Investigative Committee.
Boris Khodorkovsky, 82, who arrived at the committee's headquarters on August 6 with his lawyer, Sergei Badamishin, spent more than three hours inside the building.
Badamishin told reporters after the questioning that the case was related to the 1998 slaying of Nefteyugansk Mayor Vladimir Petukhov.
Badamishin added that his client refused to answer the majority of questions using his right not to testify against a relative.
The Investigative Committee said in June it would reopen a probe into the 1998 slaying of Nefteyugansk Mayor Vladimir Petukhov after it found new evidence suggesting Mikhail Khodorkovsky, the former CEO of the now-dismantled oil company Yukos, "might have personally ordered this murder and a number of other extremely serious crimes."
Yukos's main asset was located in Nefteyugansk at the time of Petukhov's killing.
In an August 5 statement, Mikhail Khodorkovsky said the Investigative Committee's real goal was to pressure him and his family.
Mikhail Khodorkovsky, 52, was the richest man in Russia in 2004 before being sentenced to prison in 2005 on fraud charges that he says were politically motivated.
He was released in late 2013 and currently lives in exile in Europe.
Mikhail Khodorkovsky is a vocal critic of Russian President Vladimir Putin.
Based on reporting by Interfax and TASS