New Delhi: The CBI on Tuesday questioned Vectra chairman Ravinder Rishi for the fourth time in connection with alleged irregularities in the Tatra truck supply to the Army.

Rishi who is "cooperating" so far has been asked to produce all the documents related the Tatra Sipox UK agreement with the BEML which was inked in 1997, CBI sources said.

They said at present agency is examining large number of documents which have been found during CBI searches and those provided by Rishi himself.

Sources said Rishi has told the officials that most of the documents are in his UK offices and assured that they would also be provided to the agency.

They said after going through these documents, the CBI will have clear picture other accomplices in the case and would call them for questioning.

The sources said it was in 1997 that Tatra Sipox UK signed the truck supply deal with BEML which was in alleged violation of defence procurement rules which say that procurement should be done directly from original equipment manufacturer only.

The first agreement for the supply for Tatra all terrain truck used for the transport of soldiers, heavy machinery, missile systems etc was signed with Czechoslovakia-based company Tatra in 1986.

In 1997, BEML started procuring trucks through Tatra Sipox UK, claimed to be the marketing arm of Tatra, in which Ravinder Rishi had a substantial stake.

CBI has alleged that since Tatra Sipox UK was not the original manufacturer of these all terrain trucks, the rule that defence procurements should be made from original manufacturer was violated.