Police say a final call on questioning Roopa Ganguly and Kailash Vijayvargiya is yet to be taken.
A West Bengal BJP women's wing leader Juhi Chowdhury has been arrested for pulling strings to get government funding and licences for a local NGO that was busted for running a child trafficking racket in November last.
Chandana Chakraborty who headed the NGO that ran the child care home in Jalpaiguri 600 km from Kolkata had told the police that Ms Chowdhury, the district women's wing chief, had reached out to the BJP's Roopa Ganguly and Kailash Vijayvargiya for help.
Ms Ganguly, a Rajya Sabha member, is also the party's women's wing president while Mr Vijayvargiya is the BJP's West Bengal in-charge.
Police said they will decide on the next step after interrogating Ms Chowdhury who was arrested on Tuesday evening from Darjeeling district close to the Indo-Nepal border.
The developments could put the BJP on a back-foot in a state where it has been anxious to expand its footprint in West Bengal where Mamata Banerjee-led Trinamool Congress government is in power.
Mr Vijayvargiya was quick to hit back, accusing the CID of being guided by politics rather than an impartial probe. In a tweet on Wednesday, he accused the CID of working as a "Conspiracy Invention Department" rather than being led by the available evidence.
CID officials, however, insist there was evidence which hinted at the complicity of some senior politicians.
Ms Chakraborty had told reporters in Siliguri recently that she hadn't spoken to the BJP's central leaders but Juhi did. She had named Ms Ganguly and Mr Vijayvargiya as some of the leaders Juhi had spoken to.
According to the CID, four people have been arrested in the racket for selling at least 17 children to Indians and foreigners. On paper, the NGO that Ms Chakraborty headed, showed that she had given the children for adoption.