Main accused Sanjay Roy undergoes a lie detector test in the presidential prison

New Delhi: The lie detector test of Sanjay Roy, the main accused in connection with the alleged rape and murder of a trainee doctor of RG Kar Medical College, is currently being conducted at the Presidency Jail in Kolkata, where he is being detained, officials said on Sunday.

Two more people will be tested at the CBI office in Kolkata later today, it said.

Four people, including former school principal Sandip Ghosh, were subjected to a lie detector test on Saturday, officials said.

A team of polygraphy specialists flown to Kolkata from the Central Forensic Science Laboratory (CFSL) in Delhi is conducting the tests, it said.

The CBI had previously told the Supreme Court that the crime scene had been altered at the time it took over the investigation, suggesting that the local police were trying to cover up the rape and killing of the medical doctor.

The body of the paramedic with severe injuries was found in the seminar room of the hospital's pulmonary department on the morning of August 9. A volunteer from the Calcutta police was arrested the following day.

The incident sparked widespread protests.

On August 13, the Calcutta High Court ordered the transfer of the investigation from the Calcutta Police to the CBI, which began its investigation on August 14.