The CBI on Tuesday arrested one of its lawyers and a businessman for accepting a bribe of Rs 1 crore from the father of Dinesh Dalmia, an accused in a multi-crore share scam involving his company DSQ Software.

CBI sources said Gautam Shroff, a lawyer on the CBI panel, and K.K. Rungta, a city-based businessman, had promised K.P. Dalmia that they would arrange for his son’s bail against a payment of Rs 7 crore.

“Dalmia was scheduled to pay Rs 1 crore as the first instalment to Rungta on Tuesday afternoon at his 1/1 Camac Street office. But he became suspicious at the last moment and got in touch with the CBI’s anti-corruption wing. We raided Rungta’s office and caught the duo red-handed,” said a CBI official.

Steered by the sleuths, Dalmia carried the amount in Rs 1,000 notes. When he was handing over the cash-filled bag to the duo, a four-member CBI team barged in and arrested them.

The investigating agency has charged Shroff and Rungta with accepting “illegal gratification”.

“This is the biggest corruption deal we have come across in recent times in Calcutta,” said a sleuth.

While the CBI went to town with news of the arrests on Tuesday, those who have known Dinesh and his family for years felt that the matter was not as straightforward as it was being made out to be.

“It is difficult to believe that K.P. Dalmia had tipped off the CBI about the demand for bribe for his son’s bail. There must be more to it than meets the eye,” said a trader who has known the Dalmias for years.

CBI officials refused comment on the matter.

Dinesh, former managing director of DSQ Software, has been languishing in jail since his arrest in Delhi in February 2006. The Supreme Court had rejected his bail plea thrice.

He has been accused of misappropriating Rs 594.88 crore, the sale proceeds of 1.30 crore shares of DSQ Software that were not listed on any stock exchange.

The publicly listed software services and consulting company, with a headcount of 2,000, had earned more than $150 million in revenues in 2000.

But the company, set up in 1992 in Chennai, went into a tailspin in 2002. It collapsed the next year. Dalmia was believed to be in the US between 2003 and 2006.

The CBI had filed its first chargesheet against Dinesh — against whom Interpol had also issued a red-corner notice — in September 2005, when he was on the run.

The second chargesheet was filed in July 2008. “We are interrogating the arrested duo and trying to find out their links with Dalmia and whether they had taken money from him before. They will be produced in the CBI special court on Wednesday,” said an official.

Shroff and Rungta had reportedly told K.P. Dalmia that Dinesh’s bail petition would be moved in Calcutta High Court after the Puja vacation.

Shroff had promised the desperate father that he would ensure that CBI officials probing the case would “not oppose” the bail plea.