Enforcement Directorate (ED) officers on Tuesday morning started simultaneous raids at six locations in Kolkata, including the residence of a TMC MLA, in connection with their investigation into the alleged financial irregularities at RG Kar Medical College and Hospital, an officer of the agency said.

Search operations were underway at the Sithi residence of TMC's Serampore MLA Sudipto Roy and the house of a medicine dealer, besides four other places, he said.

"These raids are as part of our investigation into the alleged financial irregularities in RG Kar Hospital. We have certain inputs due to which these raids are being conducted," the ED officer told PTI.

As a part of their probe into the alleged financial irregularities, CBI has already arrested former principal of the hospital, Sandip Ghosh and three of his associates. These irregularities surfaced after the rape and murder of woman doctor at the hospital.