Russia's Federal Security Service (FSB) have detained several employees of the Moscow department of the Russian Investigative Committee, including deputy head Denis Nikandrov, news agency Interfax reported, citing a message from the agency.
The FSB began a search of the committee's Moscow offices in connection with the case against notorious crime boss Zhakary Kalashov, or Shakro Molodoi.
"The FSB have carried out investigative actions against a number of staff members on the basis of exceeding their official powers, as well as receiving bribes from the criminal community," an FSB statement said, the Slon news website reported.
Shakro Molodoi was arrested on June 11 on charges of extorting money from the owner of the Elements restaurant in Moscow, after a violent shootout in December 2015 left two dead.
A lead investigator on the second case against the Yukos gas giant, Nikandrov was reportedly detained on Tuesday while receiving a bribe worth $1 million for Shakro's release, RBC reported.
It was reported in 2013 that the Prosecutor General's Office begun a preliminary investigation into Nikandrov for abuse of power and coercion of witnesses to testify.
In addition to the arrests, the FSB is searching the Investigative Committee's office in Moscow's center.