CBI on Saturday conducted searches at the office and printing press of Manas Publications, which has published a book written by former RAW official on the country's external intelligence agency.
The searches come a day after the CBI raided the residence of Maj Gen (Retd) VK Singh following the registration of a case under the Official Secrets Act (OSA).
It was not immediately clear what the probe agency was looking at the printer's premises as the book has hit the stands three to four months ago.
Vivek Garg of Manas Publications, who had criticised the government's move to conduct raids on Singh's house yesterday, however, was not available for comments.
Singh had irked some quarters in the government with his book "India's External Intelligence: Secrets of RAW".
The CBI has registered a case against him under Section five (wrongful communication of information) of the OSA.