Protests against Assam finance minister Himanta Biswa Sarma intensified on Wednesday with the CPM taking out a march demanding his resignation for his alleged involvement in the multicrore-rupee Saradha scam.

The 1.7km march that started from the Assam CPM headquarters at Hedayatpur to the gates of the Reserve Bank of India, Guwahati branch, is the second protest after members of the Assam Pradesh Youth Congress Committee on Tuesday tried to gherao the CBI office demanding the arrest of Sarma.

“We want the CBI to start its investigation against Himanta Biswa Sarma and since his integrity and honesty are at stake, he should step down from his posts in the state cabinet,” one of the protesters said.

The protests were triggered after Bengal chief minister Mamata Banerjee claimed having “enough evidence” against Sarma regarding his involvement in the ponzi scheme.

Deben Bhattacharyya, secretary of the Assam CPM, who led Wednesday’s march, said, “Himanta Biswa Sarma’s involvement in the Saradha scam had become apparent when CBI officials raided his residence and the TV channel owned by his wife in August 2014. At that time, he was in the Congress. Mysteriously, after he joined the BJP next year, no further investigation was conducted by the CBI into the Assam chapter of the scam, until now. Now that Mamata Barejee has released a letter by Saradha Group chief Sudipta Sen naming Sarma, I dare the CBI to restart its investigation against Sarma.”

Bhattacharyya was referring to an 18-page letter dated April 6, 2013, addressed to the CBI with Sudipta Sen’s signature on it alleging that “Hemanta Biswa Sarma (sic)” “dramatically” cheated him, which Mamata released during the “Save the Constitution” dharna in Calcutta on Tuesday.

Sarma, however, on Tuesday tweeted, “I’ve joined the investigations and offered my full cooperation as a witness. And all this happened much before I joined BJP.”