The city police on Tuesday questioned several junior doctors of the RG Kar Medical College and Hospital in connection with the rape and murder of their colleague but could not examine others they had summoned after Calcutta High Court transferred the case to the CBI, police said.

Some who were questioned on Tuesday had been called earlier, too.

Hours after the probe was handed over to the CBI, a section of junior doctors raised allegations of destruction of evidence by the state government.

“Why did the PWD start a renovation job on the same floor, just opposite the seminar hall where the incident happened? Is it not an attempt to tamper with evidence?” asked a junior doctor.

Officials of RG Kar hospital said the renovation was part of a project to build washrooms and duty rooms in the chest medicine ward, as demanded by the agitating junior doctors.

“This had been decided earlier. There was a long-standing demand (by junior doctors) to have more duty rooms and washrooms. There is no question of tampering of evidence. The seminar room is sealed and has not been touched,” said the official.

Agitators, however, protested the rush of the construction work. “If more than one person could be involved (in the crime), the rooms just opposite the seminar hall could also hold vital clues. But now it has been broken down. The timing has raised suspicion,” said a junior doctor.

The police said the scene of crime — the seminar room — had been secured and the room had been locked and was being guarded.

As news of the probe being shifted came in, the SIT started arranging to hand over files and evidence to the CBI.

Sanjay Roy, in police custody, was taken for his medical test on Tuesday evening and brought back to Lalbazar.

“We are ready to hand him over today if the CBI approaches us,” said an SIT member.