New Delhi,  In a latest development in the Chinese visa case, the Central Bureau of Investigation (CBI) on Saturday conducted searches at the residence of Congress MP Karti Chidambaram in Chennai and recovered some incriminating documents from there.

A CBI source said that when the probe agency conducted searches at the residence of Karti Chidambaram in May, a portion of the house had to be sealed as the keys were with the Congress MP's wife, who was reportedly out of the country then.

"Today, Karti Chidambaram's wife joined the probe and we opened this portion of the house. We have recovered some incriminating evidences and documents," said the source.

According to the CBI FIR, in 2011, a Mansa (Punjab) based private firm, Talwandi Sabo Power Limited, took help of a middleman and allegedly paid Rs 50 lakh to get visas issued to Chinse nationals to help get a project completed before deadline.

"The private firm was in the process of establishing a 1,980 MW thermal power plant which was outsourced to a Chinese company. The project was running behind its schedule. In order to avoid penal actions for the delay, the said private company was trying to bring more and more Chinese professionals to its site in Mansa district. For this it needed project visas over and above the ceiling imposed by Ministry of Home Affairs," said a CBI official.

The official said that for the said purpose, the representative of the private firm approached a person in Chennai through his close associate and thereafter they devised a back-door ploy to get permission to re-use 263 project visas allotted to the said Chinese company's officials.

In pursuance of the same, the said representative of the Mansa-based company submitted a letter to the Ministry of Home Affairs seeking approval to re-use the project visas allotted to the company, which was approved within a month and permission was issued to the firm.

"A bribe of Rs 50 lakh was allegedly demanded by the said private person based in Chennai through his close associate which was paid by the Mansa-based company. The payment of the said bribe was routed from Mansa to the person in Chennai and his close associate through a Mumbai-based company, reportedly controlled by Karti Chidambaram, as payment of false invoice raised for consultancy and out of pocket expenses for Chinese visa related works," said the CBI official.

Karti Chidambaram's father P. Chidambaram was the Union Home Minister then.