The search is being conducted in connection with a case opened in the spring, RBC and the security-services-linked Telegram channel Baza reported, citing law enforcement sources.
According to Baza, the case concerns the illegal use and storage of personal data committed by a group of persons. RBC did not specify which particular case is involved.
Novaya Gazeta columnist Oleg Roldugin is a defendant under the charge. According to Baza, investigators believe he may have acted either jointly with Sokolov or on his instructions.
Roldugin was detained in early April after searches at the Novaya Gazeta newsroom. The following day, the Tverskoy District Court placed him under arrest.
During the hearing it emerged that investigators had seized the journalist's equipment, hard drives and editorial ID, and had examined Telegram chats on his phone, including those with Telegram bots. In June, Roldugin was released from the pre-trial detention center under house arrest.
The BBC Russian Service linked the prosecution of Roldugin to his running of the anonymous Telegram channel Bolshche, chem fakt, which published information about the flights of business jets belonging to Dmitry Medvedev, Alexei Mordashov and Vladimir Yevtushenkov. Roldugin wrote about this in his investigations.