A CBI team conducted a search and seizure operation at the north Calcutta house of Sudipta Roy, the Trinamool Congress MLA from Serampore in Hooghly, on Saturday evening.
Roy is also the former chairman of the Rogi Kalyan Samity (Patients' Welfare Committee) at RG Kar Medical College and Hospital and president of the state medical council.
He was not at home when the CBI team turned up, sources said.
CBI officers remained tight-lipped about the search and seizure operation. "We can't talk about this now," an officer said.
The CBI earlier visited Roy's house in Sinthee last year in September in connection with their probe into alleged financial irregularities at RG Kar hospital.
The Enforcement Directorate (ED), which is also probing the alleged money trail in this case, also visited his house last year.
CBI sources said that Sandip Ghosh, the former principal of RG Kar Medical College and Hospital under whose watch a postgraduate trainee was raped and murdered there, had called Roy on the morning of August 9 to inform him about the death of the 31-year-old doctor.
Roy reached the hospital that morning after receiving the call from Ghosh.
Ghosh has been chargesheeted along with some of his alleged accomplices for corruption.