The CBI today arrested four persons, including Chief General Manager of the National Highway Authority of India, for allegedly favouring a private construction firm in allocation of contracts after which a court sent them to the probe agency's custody for five days.

Besides CGM S K Nirmal, NHAI General Manager Nitin Jain was arrested in the case after the CBI claimed to have made huge recoveries from their premises in Delhi and Jaipur, including a whopping Rs 1.86 crore from the residence and bank locker of Jain and another Rs 46 lakh from Nirmal's house.

Others arrested in the case are Managing Director of Oriental Structure Pvt Ltd K S Bakshi and one of his employees S K Dikshit, a CBI spokesman said adding that all the four were produced before a designated court which remanded them to CBI custody till May 31.

The CBI had registered a case against the four for allegedly entering into a criminal conspiracy and engaging in corrupt practices in the award of contract.

The modus operandi of NHAI officials was to eliminate all potential contenders on one pretext or the other and favour the accused company ensuring huge financial gains to it, the spokesman said.

After filing the FIR in a court, the CBI carried out searches at eight places in the national capital and Jaipur during which they claimed to have recovered Rs 1.86 crore from Jain's house and bank locker.

The agency also claimed to have recovered Rs 46 lakh from Nirmal's house besides 360 grams of gold and five kilograms of silver from his locker, the CBI said.

The spokesman alleged that NHAI officials had managed to give the contracts for projects in Maharashtra and Madhya Pradesh after entering into a criminal conspiracy with the Managing Director of the private firm.

The work included development, operation or maintenance of four-laning of Nagpur-Betul Section of NH-69 in Maharashtra under National Highways Development Project Phase-IV on Design, Build, Finance, Operate and Transfer basis through public-private partnership.

NHAI had received 13 offers for the project out of which four were rejected by the officials allegedly on frivolous grounds at the qualification stage.

Four other companies were also eliminated from the next stage of bidding by making stipulations pertaining to submission of original documents in gross violation of the conditions of the tender, the agency alleged.

It has also been alleged that the officers of NHAI gave key confidential, strategic and vital information to the company during the process of tender which in turn helped it gain greater financial benefits.