Chennai: Income Tax Department on Wednesday carried out searches at over dozen places in two states against the son and some relatives of Tamil Nadu Chief Secretary P Rama Mohana Rao during which they claimed to have seized Rs 18 lakh cash and gold bars.

The I-T action was conducted in connection with the case related to biggest cash haul of new notes post demonetisation after the department raided some sand mining operators of Tamil Nadu here.

A team of about 100 tax sleuths, aided by a platoon (about 35 personnel) of CRPF, launched the raids as early as 6 AM and visited at least 15 premises in the state and the neighbouring Andhra Pradesh as part of the tax evasion probe.

The searches, top I-T sources said, were launched against Rao's son Vivek Papisetty and his relatives and Rs 18 lakh in new notes and two gold bars of 1-kg each were seized from the premises of Vivek's father-in-law based in Chittoor of AP. Rao and his son could not be contacted for their comments.

The latest action is a follow up against the sand mining operators in the state and few others including Sekar Reddy, who was removed as the Board Member of the Tirumala Tirupathi Devasthaman (TTD) (Tirupati) by the AP government after the I-T action on December 9.

Reddy has also been arrested by the CBI today. The sources said Rao was "fully cooperating" with the sleuths during the operation after they searched his premises in the state capital here, even as they recorded Vivek's statement.

The department, they said, got "leads" in the sand mining probe case they were investigating and hence went to search Vivek and few others.

The tax officials, from the investigation wing of the department here, also visited the state secretariat for fetching two mobile phones of the Rao family.

Rao was appointed the state's top bureaucrat in June this year by the state government led by late Chief Minister J Jayalalithaa.

In order to keep the operation secret, the I-T department sought assistance of central paramilitary CRPF rather than calling in the state police forces.

They added that similar action is being carried out on the premises of a retired Indian Forest Service officer working with the state Environment Impact Authority, and few others. The searches, they said, are the "outcome" of the department's probe in the biggest haul of cash and gold early this month here, post demonetisation, in which over Rs 142 crore unaccounted assets have been recovered so far apart from Rs 34 crore in new notes.

The total cash seizure in this instance was over Rs 170 crore and this has become the single largest case of disclosure of undisclosed assets post the note ban.

Meanwhile, the Enforcement Directorate (ED) too has registered a money laundering complaint in this case after the tax department shared official documents with the agency.