Kolkata/IBNS: The Central Bureau of Investigation (CBI) conducted searches at 15 locations across Kolkata on Sunday morning in connection with allegations of financial irregularities against RG Kar Medical College's ex-principal Sandeep Ghosh, following the brutal rape and murder of a junior doctor at the hospital premises.

According to reports, a CBI team reached Ghosh's house at 6.45 am, but he opened the doors to them only at 8 am.

The CBI also searched the house of Debashish Som, who works in the state's forensic department, in Kolkata's Beleghata neighbourhood.

Other CBI teams have searched the houses of former hospital superintendent Sanjay Vashisht, and medical supplier Bipal Singh in Howrah district's Hatgachha area.

According to reports, the CBI can record the statement of Akhtar Ali, the whistleblower whose information led to a corruption investigation against the former principal of the Kolkata hospital.

Ali had raised this matter in the Calcutta High Court, after which the Kolkata Police's special investigation team had recorded his statement.

Akhtar Ali worked at RG Kar Medical College and Hospital for 16 years. He began as assistant superintendent in grade 2, went to grade 1, and became Deputy Superintendent.

"Before Sandeep Ghosh came, this was the number one college in eastern India. It is a 100-year-old college. I have exposed a lot of scams. The first scam was to make students fail. They used to extort money from them, those who did not listen, and some students used to collect this money," Akhtar Ali alleged.

"They used to make junior students drink alcohol and make them protest, whenever it came to Sandeep Ghosh's transfer. The illegal activities include smuggling of bodies, biomedical waste scam. The complaints went to the higher levels including vigilance, but nothing happened," Akhtar Ali said.

The key suspect in the rape and murder case of the junior doctor has been identified as Sanjay Roy, a civic volunteer, who was seen on the hospital's CCTV near the crime scene.

Sanjay Roy, Sandeep Ghosh, and some doctors whose fingerprints were taken from the seminar hall, where the junior doctor's body was found, have been made to undergo polygraph tests.

The CCTV footage shows Sanjay Roy entering the hospital at 1.03 am, media reports said.

During interrogation, the police had shown him the CCTV evidence, after which Sanjay Roy admitted to the crime, media reports said.

Before he reached the hospital at 1.03 am the night the junior doctor was raped and murdered, Sanjay Roy had gone to two brothels in Kolkata, the police have said.

He went to the red light area Sonagachi on August 8 night, drank alcohol, and visited two brothels one after another, sources had said.