The polygraph test of Aftab Ameen Poonawalla will be conducted on Wednesday at the Forensic Science Laboratory in Rohini.

Official sources said that a pre-medical session to gain some preliminary information which will be later used to develop diagnostic questions, as well as a scientic session was conducted on Aftab at the FSL office on Tuesday evening.

"However, the main polygraph test which will involve a questionnaire prepared by the Delhi Police investigators will most likely be taken up on Wednesday."

The sources said that the a polygraph and a marco test is imperative in the Shraddha Walkar murder case as Aftab, during the interrogation, has been deceptive in nature and tried to mislead the interrogators.

The police feel that Aftab committed the murder with foolproof planning and not in a fit of rage.

A polygraph test, commonly known as a lie detector test, is a procedure in which physiological indicators of a person such as blood pressure, pulse, and respiration, are recorded while he is answering a series of questions.

On Tuesday, the officials from FSL, as per protocol, also went to the court to verify the order of the copy for the polygraph test.

Sources further told IANS that police teams will try to conduct both the tests (Polygraph and Narco) within four days

Meanwhile on Tuesday evening, Delhi Police Commissioner Sanjay Arora on Tuesday evening reached South Delhi's DCP office. The CP spoke to investigators and took stock of the ongoing probe.

According to sources, investigators have to join the dots on the evidence collected so far as they are not being able to conclude the investigation on the basis of Aftab's statements.

"Multiple agencies have been working on the case and we will file a collective report in the court. The charge sheet will be filed on the basis of forensic evidence," said the sources.

Aftab will also be taken to two ponds for the search of the body parts, one in the Mehrauli forest and the other in Maidangarhi.

On Sunday, the police teams had recovered more human remains from the Mehrauli forest.

They have so far sent 18 bones, including the base of a skull, and a decapitated jaw, for forensic examination.

To ascertain whether the bones are that of Shraddha's, the blood samples of her father and brother have been collected for DNA analysis.

So far, the place of offence, the rented accommodation in Chattarpur, has been closely inspected by the crime team and experts from forensics.

From the house, multiple exhibits have been seized, while blood stains were found in the kitchen and bathroom.

However, weapons used to commit the murder are yet to be discovered.