The Central Bureau of Investigation (CBI) on August 13 took over the case of rape and murder of a medic working at Kolkata's R G Kar Medical College and Hospital, which has sent shockwaves over the country.
The body of the victim was discovered in the hospital's seminar hall on August 10, following which there have been protests across the country.
The Calcutta High Court, two weeks back, handed over investigations into the case to the CBI.
Since then, the central agency has been grilling the former principal of R G Kar, Sandip Ghosh, and has also conducted polygraph tests of the chief accused, Sanjoy Roy, who was arrested by the Kolkata Police, as well as Ghosh.
Here is what the CBI probe has revealed so far:
The direction was passed in the wake of a petition moved by the victim’s parents praying for a court-monitored probe and multiple other PILs seeking probe transfer to the CBI.
The interim order came five days after the gruesome incident had come to light and five days ahead of the probe deadline of Sunday (August 19) issued to the police by Chief Minister Mamata Banerjee, beyond which she had vowed to hand over investigations to the central agency.
The CBI swiftly completed all the formalities within hours of the Calcutta High Court order directing the state police to hand over the case documents to the central probe agency.
A team of CBI officials from Delhi along with forensic scientists and medical experts visited Kolkata on August 14.
According to the laid down procedure, the CBI re-registered the FIR of the Kolkata Police. Whenever the CBI takes over a case from any state police, it starts with the registration of the police FIR as its own case.
The final report of the agency giving its findings is submitted before a special court which may or may not differ with the allegations in the FIR.
The West Bengal Doctors' Forum wrote to the CBI, alleging that attempts were being made to tamper with evidence by carrying out construction work near the spot where the body of the female doctor was found.
"We have come across reports of sudden civil reconstruction works in and around the scene of crime at the same institution. We are extremely apprehensive about the motive behind such an effort and we think that this might hamper the investigation by tampering with important evidence," said the letter, signed by Dr Koushik Chaki and Dr Sanjoy Holme Chowdhury.
"We have informed the same to the state health secretary. We request you to look into the matter with utmost care and due regard the same deserves to ensure justice to the slain lady doctor," it said.
Three groups of CBI officers have been formed to investigate the matter, an official of the central agency said.
"One group will visit the RG Kar Medical College and Hospital, and talk to the witnesses and the doctors who were on duty on that night. Another team will take the arrested civic volunteer to a local court after medical tests and plea for his custody, while another will coordinate with the Kolkata Police sleuths who were conducting the investigation," an official told PTI soon after taking over the investigation.
Mamata Banerjee welcomed the Calcutta High Court order granting a CBI probe into the case and said, “We would abide by the Calcutta High Court’s order and extend all support to the CBI. We have no problem with CBI being handed over the case as we want it solved at the earliest."
CBI officers on Thursday, August 15, visited the residence of the victim and spoke to her parents as a part of their investigation.
The investigators took note of the time they received the call from the hospital, informing them about the death of their daughter.
The officers also asked them about their daughter's friends, and whether she complained of any problems at the state-run RG Kar Medical College and Hospital where she was a postgraduate trainee doctor, he added.
"It was difficult to speak to a couple who have lost their daughter in such a manner," the officer said.
The CBI also interrogated five doctors of the hospital, its former medical superintendent-cum-vice-principal (MSVP), principal, and the head of the Chest Department where the victim's body was found, he said.
The CBI also spoke to the officer-in-charge of the Tala police station, under the jurisdiction of which the hospital is located.
The investigators have sought details of Civic Volunteer Sanjay Roy's call detail record and mobile tower location, among others. He was arrested after the victim's body was found on Friday.
"We are also looking into data consumed by his mobile to ascertain whether he made any video or internet voice calls," the officer said.
The parents of the victim told CBI that a few interns and physicians of R G Kar were involved in the crime, an officer said on Friday.
The parents also provided the central agency, which is conducting the probe into the case on an order of the Calcutta High Court, with names of those who they suspect to be associated with their daughter's killing in the state-run hospital.
"The parents told us that they suspect the involvement of multiple persons behind the sexual assault and murder of their daughter. They have given us names of a few interns and doctors working with their daughter at the RG Kar Hospital," a CBI officer said.
The central agency officer said that they were giving priority to questioning the doctors and officers of the Kolkata Police who were part of the investigation.
"We have zeroed in on at least 30 names whom we will be calling for questioning. We have already started questioning them," he said.
The CBI, on August 16, had summoned one house staff, two post-graduate trainees (PGTs) who were on duty with the doctor on that night when she was murdered.
At RG Kar hospital, the investigators collected samples on August 17 and sent those to the Central Forensic Sciences Laboratory for testing, an officer said.
"At the KP barrack, the team spoke to the policemen who are staying there and enquired about the accused's movements on Friday morning. They took the details of when Roy returned to the barrack and what he did after reaching there," he said.
Later, the same team reached Sambhunath Pandit Street in South Kolkata, Roy’s rented residence, and spoke to his mother about his recent whereabouts and recorded her written statement, the officer said.
During his first round of questioning, the former principal was asked about his first reaction after getting the news of the doctor's death, who he instructed to inform the family and who contacted the police, he said.
CBI officials enquired about the weekly roster of the chest medicine department where the victim was seen to be put on duty for a gruelling 36 hours at a stretch or, at times, even 48 hours, the officer said.
"Some of his answers were convoluted. He was grilled till early Saturday and then allowed to leave for home," the officer told PTI.
The CBI was later granted permission to conduct a polygraph test of the accused.
CBI detectives conducted technical tests on the vehicle used by Ghosh.
They also questioned the driver of the vehicle that Ghosh was using as the principal of the RGKMCH, a police official said.
"Forensic experts have examined the vehicle to find out the details of its movements. We are also trying to know whether the vehicle was used to carry something. We have also spoken to the driver of the vehicle to find out the details," he told PTI.
The CBI alleged in the Supreme Court on August 22 that there was an attempt to cover up the case by the local police as the crime scene was altered by the time the federal agency took over the probe.
Appearing in the court on behalf of the CBI, Solicitor General Tushar Mehta told a bench headed by Chief Justice D Y Chandrachud that senior doctors of the hospital as well as the victim's colleagues had asked for videography, which means even they had felt that there was a cover-up.
"We entered the probe on the fifth day. Before that, whatever was collected by the local police was given to us. The investigation itself was a challenge because the scene of offence was altered. The FIR was registered only after the (victim's) cremation at 11:45 pm.
"First, the parents of the victim were informed by the deputy superintendent (of the hospital) that she was not well. When they reached the hospital, they were told that she had committed suicide..... Fortunately, the colleagues of the deceased insisted for videography. This suggests that they were suspecting a cover-up," Mehta told the bench, also comprising Justices J B Pardiwala and Manoj Misra.
The solicitor general further submitted that when a call was made to the Tala police station in the morning of August 9, the doctors told the cops that the victim was unconscious, although she was already dead.
Appearing in the court on behalf of the West Bengal government, senior advocate Kapil Sibal opposed Mehta's submissions, saying everything was videographed and nothing was altered at the crime scene.
On the same day, the CBI sought polygraph tests of Ghosh and four other doctors in connection with the case.
The CBI is concentrating on how the crime was executed without any hindrance in the facility’s seminar hall where the door’s tower bolt was found broken, an officer said.
CBI officials are also trying to find out if someone was stationed outside the seminar hall to ensure that the crime went undisturbed, he said, adding that the investigators are analysing CCTV footage to confirm it.
The investigating officers wondered why nobody could hear any sound from inside the seminar hall when the victim was being tortured.
"The tower bolt was broken, which caused the door to malfunction. We are probing whether anyone was stationed outside to act as a guard while the crime was committed," a CBI officer told PTI.
Initial findings indicate that the door, due to the broken tower bolt, had been malfunctioning for some time. The victim entered the hall between 2 AM and 3 AM on August 9. A doctor on duty reported seeing her asleep inside the hall, the officer said.
"Interviews with doctors, interns, and junior doctors revealed that the door’s malfunction had been a known issue, which prevented the victim from locking the door that night," he added.
The Calcutta HC on August 23 ordered the transfer of the investigation into alleged financial irregularities at RG Kar from a state-constituted Special Investigation Team (SIT) to the CBI.
The decision followed a petition by former deputy superintendent of the medical establishment, Akhtar Ali, who sought an investigation by the Enforcement Directorate (ED) into alleged financial misconduct during the tenure of the college's former principal, Ghosh.
CBI sleuths on Sunday launched search operations on the premises of Ghosh, ex-MSVP Sanjay Vashisth and 13 others in and around Kolkata.
The anti-corruption unit of the CBI also searched the residences and offices of those engaged in supplying materials for management and care of patients.
At least seven officers of the central probe agency were questioning Ghosh at his Beliaghata residence since 8 am on Sunday, while others were grilling Vashisth, the former medical superintendent and vice principal of the hospital, and another professor of the forensic department of the medical establishment, among others, they said.
Accompanied by a huge team of central forces, the CBI team, which reached Ghosh's residence around 6 am, was made to wait for nearly one-and-half hours before he opened the doors, the officials said.
Another team of CBI officers also conducted searches at the ex-principal's office at the hospital and also went to the canteen in the academic building.
The lie detection test on Sanjay Roywas carried out at Kolkata's Presidency Jail where he is lodged, officials said on Sunday.
CBI named Ghosh in the FIR the agency filed in connection with its probe into the alleged financial irregularities at the institution during his tenure.
The agency has slapped Section 120B of IPC (criminal conspiracy) read with Section 420 IPC (cheating and dishonesty) and Section 7 of Prevention of Corruption Act, 1988 (amended in 2018) which covers unlawful acceptance of gratification by a public servant.
The cases read together account for cognisable offences and are non-bailable in nature, a senior Calcutta High Court lawyer said.
Besides Ghosh, the CBI has also registered cases against one M/s Ma Tara Traders of Madhya Jorehat, Banipur, Howrah, M/s Eshan Cafe of 4/1, H/1, JK Ghosh Road, Belgachhia, Kolkata and one M/s Khama Louha.
The FIR was lodged on the basis of a written complaint lodged by Debal Kumar Ghosh, special secretary to the state health department.
On Monday, Ghosh was subjected to a second round of polygraph tests.
With DH Web Desk inputs