The central bureau of investigation (CBI) on Monday conducted raids at the premises of former telecom minister Dayanidhi Maran after registering a case against him in connection with the controversial Aircel-Maxis deal.

The agency has also booked his brother Kalanidhi Maran, Maxis owner T Ananda Krishnan, senior executive Ralph Marshall and three companies Astro, Maxis and Sun TV in the case on charges of criminal conspiracy under IPC and Prevention of Corruption Act.

After registering the case, the agency carried out searches at the premises of Maran brothers in Delhi and Chennai.

"CBI has registered case against Maran brothers, Ralph Marshall and T Anandkrishnan and three companies under section 120b of IPC read with 13(2) with 13 (1)(d) and also section 7 and 12 of the Prevention of Corruption Act. Case was registered on October 9. Searches were conducted at Delhi and Chennai," CBI spokesperson Dharini Mishra said here.

It has been alleged by former Aircel chief C Sivasankaran that Maran as the then telecom minister favoured Maxis-group in the takeover of his company and in return investments were made by the company through Astro network in Sun TV owned by Maran family.

The CBI, in its recent status report to the supreme court, had said that during Maran's tenure there was "deliberate delay" to provide letter of intent to Sivasankaran.

The agency had said that after Aircel was sold to Maxis investments were made by the Malaysian firm into the family business of Marans.

Former aides of Maran had reportedly told CBI that the processing of the files of Sivasankaran was delayed allegedly at the direction of the minister, agency sources claimed.

Maran had refuted the allegations.

It was also contended that Marshall held meetings with the telecom minister between 2005 and 2006.

Sivasankaran had alleged that his applications for licences were rejected when Maran was telecom minister in 2006, forcing him to sell his company to Maxis, whose owner is considered to be close to Maran and his brother Kalanidhi, who owns Sun TV.

Later, Maran is alleged to have granted 14 licences to Dishnet Wireless (Aircel) during his tenure as the telecom minister. The allegations have been refuted by Maran.

CBI is looking into financial transactions of Sun TV and Maxis. Besides, it is also looking into various aspects of takeover of Aircel by Maxis group, the sources said.

The probe agency has already registered a preliminary enquiry on issues in 2G spectrum allocation between 2001-07 and is actively looking into matter.