The CBI is likely to carry out narco-analysis on the driver and helper of the truck that hit the Unnao rape survivor's car and may seek their custody in this regard, officials said on Monday.
The CBI had subjected the two to a lie-detector test in its office and brain mapping at Forensic Science Laboratory, Gandhinagar, Gujarat but the report is still awaited, they said.
The agency is yet to speak to the victim, allegedly raped by expelled BJP MLA Kuldeep Singh Sengar, and her lawyer who are under treatment at the All India Institute of Medical Sciences as doctors have said that they are medically unfit to for any interaction, they said.
The survivor was airlifted from King George's Medical University in Lucknow to AIIMS for better care as she continued to be critical.
The car in which the victim and her lawyer were travelling was hit by the speeding truck, which was coming from the opposite direction on the wrong side and had its number plate smeared with black paint, in Gurubakshganj area of Rae Bareli on July 28.
In the accident, the victim and her lawyer were critically injured while both her aunts were killed.
In the absence of interaction with the two survivors-- the rape victim and the lawyer-- the CBI is depending on expert opinions and eye-witness accounts to recreate the sequence of the accident, they said.
In narco-analysis, a person is injected with chemicals known as barbiturates commonly called truth serum to bring out repressed thoughts and memories.
The polygraph test measures vital body parameters when a question is put before a person. The variations in these parameters indicate whether a person is truthful or not.
Brain mapping uses neuroscience techniques to see the brain's reaction of a person when pictures and information related to an event is placed before them.
All the three techniques do not have any value as evidence in the courts but they are used to bring forth hidden information which could lead to the recovery of material or information to be used during the trial or apprehension of an accused.
"We are hopeful to complete the probe within two weeks as directed by the Supreme Court. We are moving in the right direction," a CBI official said.
The apex court, which had earlier given two weeks to the CBI to complete the probe, extended the time by another two weeks while noting that the probe agency has done "quite extensive investigation" so far in the case.
The CBI has booked Sengar and nine others on murder charges in connection with the truck-car collision.
The state government has come under severe criticism for failing to provide security to the 19-year-old woman who was allegedly raped by the BJP MLA in 2017.
Her uncle Mahesh Singh, who is lodged in Rae Bareli prison, has alleged that false cases were slapped against him by people close to Sengar for not yielding to the pressure after his niece accused the MLA of raping her and he has been transferred to Rae Bareli prison where a threat to his life looms.
The police had arrested Singh and he was transferred to Rae Bareli prison.
Singh, who lost his wife and sister-in-law in the accident, has also alleged that complaints by the victim's family were not paid heed to by the local police, the FIR said.
On Tuesday, the Centre handed over the probe to the CBI on the recommendation of the Uttar Pradesh government.
The Uttar Pradesh Police had on July 29 filed a murder case against Sengar and nine others after the rape survivor's family filed a complaint, alleging "conspiracy" behind the car crash.
