The CBI on Tuesday sent summons to two police officers, including a DSP, asking them to join investigations into the multi-crore gutkha scam.
Sources said the summons were issued to DSP Mannar Mannan and Inspector Sampath Kumar to appear before the agency for interrogation.
The move comes a day after a special court in Chennai sent five persons, including three gutkha manufacturers, to four-day CBI custody in the case.
A V Madhava Rao, Uma Shankar Gupta and Srinivasa Rao, owner and directors of MDM gutkha company, Food Safety and Drug Administration department official P Senthil Murugan and Superintendent of Central Excise department N K Pandian were sent to judicial custody till September 20.
The gutkha scam relates to bribes to the tune of Rs 40 crore being paid allegedly to Health Minister C Vijayabhaskar, DGP T K Rajendran and George to allow illegal sale of gutkha in the state from 2013, when the ban on such products came into force, to 2016.
The arrest of Rao and his associates is significant since the entries in Rao's diary, which was recovered during an Income Tax raid in 2016 on his premises, forms crucial evidence in the case.
The arrests followed massive raids at 35 locations in Tamil Nadu, including the residences of Vijayabhaskar, Rajendran and George, and in other states for the past two days in connection with the scam.