NEW DELHI, Jan 20 — For the first time in the politically sensitive Bofors case pay-off case, the Hinduja brothers, one of the main accused, were interrogated by the CBI here today.

The three brothers — London-based group Chairman S.P. Hinduja and the group president G.P. Hinduja as well as Geneva-based P.P. Hinduja, entered the CBI headquarters around 3 p.m. accompanied by a battery of lawyers.

“We are fully cooperating with the investigating agency,” S.P. Hinduja said while coming out of the CBI office.

The Hinduja brothers had engaged in a prolonged litigation in the Swiss court to prevent the transfer of several vital documents relating to 155mm Bofors gun deal, to the investigating agency.

The CBI focussed its interrogation on Srichand Hinduja, the eldest of the three. He was closeted for over three hours. His younger brothers left the CBI headquarters in less than half an hour.

The CBI’s interrogation following Special Judge Ajit Bharihoke order asking the Hinduja brothers to present themselves before the premier investigating agency for questioning.

The CBI spokesman told reporters that the CBI would decide later tonight the time when G.P. Hinduja and P.P. Hinduja would be questioned tomorrow.

“A team comprising of Deputy Inspector General O.P. Ghelotra and DSP Keshav Mishra did the questioning,” he said.

The spokesman was non-committal on the question whether S.P. Hinduja would be required for further questioning.

Asked about the conviction of the accused in the case, he said the agency filed a charge sheet before a court of law only when it was confident that the case would result in conviction.

Refusing to comment on the details of the interrogation, he said “the role of the Hinduja brothers in the case is being further probed.”

The CBI has charged them of receiving kickbacks to the tune of 81 million Swedish kroners from Bofors which bagged the Rs 1437-crore gun contract in 1986.

While posting for Monday hearing of Hinduja brothers’ application seeking permission to go abroad, the judge said “if need be the three brothers can be questioned by the CBI tomorrow and day after during the working hours.”

The Hinduja brothers have been charge sheeted under Section 120-B (criminal conspiracy) and Section 420 (cheating) of the IPC and under the Prevention of Corruption Act.