The anti-corruption branch of Central Bureau of Investigation (CBI) on Monday arrested former principal of RG Kar Medical College and Hospital, Sandip Ghosh, in connection with alleged financial irregularities in the medical establishment during his tenure.Ghosh was questioned for the 15th day at the agency’s Salt Lake office over the alleged rape and murder of the RG Kar hospital post-graduate trainee on August 9. After a day-long questioning by the special crime branch, anti-corruption unit picked Ghosh in the evening and left for Nizam Palace office.