The Central Bureau of Investigation (CBI) team on Sunday took along the four accused persons in the Hathras case for polygraph and brain mapping, police said.
Yesterday, the CBI took the accused to Gandhinagar in Gujarat from Aligarh Jail.
The Supreme Court had directed that the Allahabad High Court will monitor the probe, conducted by the CBI, into the case.
The 19-year-old woman had died of her injuries at Delhi's Safdarjung Hospital on September 29 after being assaulted and allegedly gang raped in Uttar Pradesh's Hathras.
Her body was cremated by the Uttar Pradesh Police and the administration allegedly without the consent or the presence of the victim's family.