"We have sent a legal notice to West Bengal Housing minister Gautam Deb seeking to know why he has made such comments without knowing the original facts," Roy's lawyers Bipul Kundalia and Rajdeep Majumdar told PTI here.
The notice says that if Deb does not reply and does not apologise publicly for the derogatory comments, we will file a civil defamation as well as criminal defamation, the counsels said.
The notice was sent to Deb by speed post during the day, Majumdar said.
Deb had allegedly commented on the source of funds of the Trinamool Congress at a meet the press programme here and that black money was being used.
He had also alleged that only Banerjee, the Trinamool Congress supremo and Roy, the party general secretary, knew about the source of funds.