Indian police have raided the homes of former minister Dayanidhi Maran following allegations of his involvement in the country's biggest corruption scandal, officials say.
Mr Maran resigned in July after he was named in the scandal over telecoms licences. He has denied any wrongdoing.
His party colleague, former telecoms minister Andimuthu Raja, is already in jail on corruption charges.
The multi-billion dollar scandal has damaged the government's reputation.
India may have lost as much as $39bn in revenue, a sum equivalent to the annual defence budget, the state auditor has said.
Mr Maran, who was the federal textiles minister, is being investigated as part of a broader inquiry into alleged offences committed over a decade. He belongs to DMK, a key ally of the governing Congress party.
He has denied allegations that he coerced the founder of the mobile phone firm Aircel to sell off his stake to Malaysia-based Maxis.
Indian media reports said India's Central Bureau of Investigation (CBI) had raided Mr Maran's homes in Delhi and in the southern cities of Chennai and Hyderabad early on Monday.
The homes and offices of Mr Maran's brother, Kalanidhi Maran, have been also raided.
Kalanidhi Maran owns the SUN TV network, which allegedly received a kickback from from Maxis. He denies the allegation.
Investigators have also registered a case against the brothers under India's Prevention of Corruption law.
Dayanidhi Maran left the telecommunications ministry in 2007 to be succeeded by Mr Raja and was until July the country's textiles minister.
In May another senior member of the Tamil Nadu-based DMK party to be implicated in the scandal was arrested and sent to prison.
Kanimozhi - a member of parliament and the daughter of the state's former chief minister M Karunanidhi - denies conspiracy and bribery allegations in relation to the alleged misselling of the telecoms licences.
Several top company executives have also been arrested in connection with the so-called 2G case.
India has the world's fastest growing mobile phone market, with about half-a-billion subscribers.