The CBI on Wednesday arrested S Bhaskararaman, a close associate of Lok Sabha MP Karti Chidambaram, in connection with a Rs 50 lakh alleged bribery case for clearing visas of 263 Chinese nationals working at Talwandi Sabo Power Ltd in Punjab, officials said.

The bribery incident is reported to have taken place in 2011 when Karti Chidambaram's father P Chidambaram was the Union home minister.

The CBI took Bhaskararaman for questioning late Tuesday night and he was placed under arrest in the early hours of Wednesday, the officials said.

The agency has alleged that Bhaskararaman was approached by Vikas Makharia, the then associate vice president of Talwandi Sabo Power Ltd (TSPL), for the reissue of project visas for 263 Chinese workers working at the Mansa-based power plant which was in the process of being set up.

The CBI FIR, which contains the findings of the investigating officer who probed the PE, has alleged that Makharia approached Karti through his "close associate/front man" Bhaskararaman, the officials said.

"They devised a back-door way to defeat the purpose of ceiling (maximum of project visas permissible to the company's plant) by granting permission to reuse 263 project visas allotted to the said Chinese company's officials," they said.

Project visas were a special type of visa introduced in 2010 for the power and steel sector for which detailed guidelines were issued during P Chidambaram's tenure as the home minister but there was no provision of reissue of project visas, the FIR alleged.

"As per prevalent guidelines, deviation in rare and exceptional cases could be considered and granted only with the approval of the Home Secretary. However, in view of the above circumstances, the deviation in terms of reuse of project visas is likely to be approved by the then Home Minister...," it further alleged.

Makharia allegedly submitted a letter to the Home Ministry on July 30, 2011, seeking approval to reuse the project visas allotted to his company, which was approved within a month and permission was issued, the officials said.

On August 17, 2011, Makharia, on being directed by Bhaskararaman, sent a copy of the above letter dated July 30, 2011 to him through e-mail which was forwarded to Karti... Bhaskararaman after discussion with P Chidambaram, the then Home Minister, demanded an illegal gratification of Rs 50 lakh for ensuring the approval," the FIR alleged.

It alleged that the payment of the said bribe was routed from TSPL to Karti and Bhaskararaman through Mumbai-based Bell Tools Ltd with payments camouflaged under two invoices raised for consultancy and out of pocket expenses for Chinese visas related works.

Makharia had later thanked Karti and Bhaskararaman on email, it added.