A letter purportedly written by the arrested Saradha Group head Sudipto Sen has turned the heat on Assam health minister Himanta Biswa Sarma.
On Wednesday, RTI activist Akhil Gogoi sought the resignation of Sarma, who, Sen alleged, had 'blackmailed' him for cash.
Saradha Group had in the past four years spread its network of deposit collection centres, set up a biscuit factory in Dhubri and launched Northeast edition of Bengali daily Sakalbela and English daily Seven Sisters' Post.
Both publications folded up in March while the other businesses have been sealed.
CM Tarun Gogoi, meanwhile, said he was "seriously contemplating CBI inquiry against some companies for swindling public money".