The Supreme Court has revived a probe against the Adani group in an alleged case of over-valuation of coal imported from Indonesia between 2011 and 2015.

The apex court stayed a ruling of the Bombay high court, which quashed all letters rogatories (LR) sent by the directorate of revenue intelligence (DRI) to Singapore and other countries, and issued a notice to the Adani group.

A letter rogatory is a formal request to a country, with which there is a legal assistance treaty, for assistance in accessing information in connection with an ongoing probe.

Solicitor general Tushar Mehta, appearing for the directorate of revenue intelligence, contended before the apex court that the investigation into the matter should continue.

The apex court bench, headed by Chief Justice S.A. Bobde, will now hear the matter after two weeks.

In October last year, the high court had ordered the quashing of all letter rogatories sent by DRI to countries, including Singapore, against three Adani group companies accused of overvaluing coal brought from Indonesia.

The DRI probe is not restricted to Adani alone.

The investigations cover 40 companies including Anil Dhirubhai Ambani Group (ADAG) and the Essar group. Under lens are coal imports of over Rs 29,000 crore between 2011 and 2015.

In September last year, Adani Enterprises Ltd had moved the high court, seeking the quashing of the letter rogatories which were issued in 2016 after a Singapore court allowed India’s request to access documents.

A division bench of the high court, while quashing the letters had noted that due process was not followed.

In March 2016, DRI initiated investigation against a few Adani group firms for allegedly over-invoicing coal imports from Indonesia.

The letter rogatories were issued to Singapore, Dubai and Hong Kong seeking assistance in accessing documents in possession of three state-owned banks in connection with the transactions under investigation.