The body of the 31-year-old PGT trainee doctor was recovered on the morning of August 9 from the seminar room within the hospital premises.

According to reports, CBI sleuths have secured a crucial document showing that Ghosh issued the permission letter to state PWD to carry out the renovation work in a room and toilet adjacent to the seminar hall, where the brutal rape and murder is believed to have occurred.

The permission letter reportedly bears the signature of Ghosh

The renovation work commenced on August 13 evening, just hours after a division bench of Calcutta High Court ordered CBI to take over the probe from Kolkata Police.

However, that renovation work could not be carried out following massive protests by the junior doctors at the hospital premises as soon as the work started.

Ghosh is at present in CBI custody over financial irregularities carried out at RG Kar Hospital.