The lie detection test on Sanjay Roy, the main accused in the alleged rape and murder of a RG Kar Medical College trainee doctor, is underway at Kolkata’s Presidency Jail where he is lodged, officials said on Sunday. Two more individuals will undergo the test at the CBI office in Kolkata during the day, they said. Four people including former principal Sandip Ghosh underwent the polygraph test on Saturday, the officials said.

The CBI has sought permission from court to put seven people including Roy and former principal of the medical college Sandip Ghosh through the lie detector test. The test cannot be used as evidence during the trial but findings give the agency a direction for the further probe.