Kolkata/IBNS: The Central Bureau of Investigation has tracked the calls the officials and doctors at Kolkata's RG Kar Medical College and Hospital, where a 31-year-old trainee doctor was raped and murdered last month, received from an overseas number on August 9 morning, media reports said.

The crime, which sent a shockwave across the country and triggered widespread protests, was committed on the intervening night of August 8 and 9.

The CBI has tracked the call details of the officials and doctors who were present at the crime scene. The doctor was raped and murdered at the seminar hall.

Theough the probe agency has learnt that the incoming calls were from an overseas number, it is yet to trace the owner of the number.

But the CBI has learnt that the number is a prepaid and rechargeable sim card.

As per reports, the CBI officials have forwarded the number to their higher authorities so that they can connect to the external affairs wing of the particular country to track the details of the sim card owner.

Reportedly, the officials and doctors who received the calls are close-confidantes of ex-college principal Dr. Sandip Ghosh, who was on Monday arrested by the CBI in connection with the financial irregularities in RG Kar Hospital.

The only arrest in the crime was made so far by the Kolkata Police, which swiftly nabbed civic volunteer Sanjoy Roy. Sanjoy has denied committing the murder.

Junior doctors and protesters suspect the crime was committed by more than one and an attempt to tamper with evidence and cover up the crime is at play right from the beginning.

The Mamata Banerjee government is now in a crisis as people's protests roil the state challenging the state administration, which was marred by political violence and rampant corruption cases for more than a decade now.

The administration's swift run for the last rites of the victim and demolition work near the crime scene have raised some uncomfortable questions for the state administration, which is helmed by Chief Minister Mamata Banerjee who holds both the police and health portfolios.