The Central Bureau of Investigation has summoned Ashok Todi, the main accused in the case relating to death of computer graphics teacher Rizwanur Rehman who had married the Hindu industrialist's daughter Priyanka, and three others for a final round of questioning.

CBI sources said Todi, his brother Pradeep and two others including Papu, who allegedly took money to break up the marriage between Rehman and Priyanka, have been summoned to the CBI headquarters to face a few questions before the agency wraps up its investigations into the case.

Sources said it was turning out to be a case of suicide, but the victim had been forced to take the extreme step allegedly at the behest of the close kin of Priyanka's family.

The sources said the Todis would be offered to undergo a polygraph test as according to the law, the test cannot be conducted without personal consent.

The probe into the death of Rehman was reaching its final stage, sources claimed.

There have been clear indications that this relative of the girl had allegedly used pressure tactics to drive Rehman to such a stage where he took the extreme step of committing the suicide, they said.

Last month, the CBI had registered a case against the industrialist father-in-law of Rehman, Ashok Todi, and others under Section 302 (murder) of Indian Penal Code.

The Kolkata police officials, who allegedly "pressurised" Rehman and Priyanka to separate, were also quizzed by CBI.

The CBI sources said the agency would recommend Regular Departmental Action at least against two Kolkata policemen for alleged intimidation.