While investigating the sand mines in South India two French journalists were held on charges of espionage by Tamil Nadu State police.
Allegedly the journalists were spying on an assignment for which Indian journalists had been threatened for reporting on the issue.
Arthur Bouvart and Jules Giraudat arrived in Tamil Nadu state in November to investigate the environmental impact of mining sand, a resource that has become scarce and increasingly lucrative amid a decades-long Asian construction boom.
The journalists, who were in India on tourist visas, work for Forbidden Stories, which pursues investigations other reporters have been killed, jailed or threatened over.
Tamil Nadu has allegedly been the site of rampant illegal extraction of sand and other beach minerals, which activists estimate could have cost the state exchequer at least $300m (£235m) in lost revenues.
Indian journalist Sandhya Ravishankar says she was stalked and harassed last year after publishing a series of investigative reports into the industry, which she alleged was allowed to operate illegally by colluding with state and federal officials.
According to a report filed by the Tamil Nadu state police, Bouvart and Giraudat entered a facility belonging to Indian Rare Earths Limited (Irel), a national mining agency, and spent five minutes on the premises before they were asked to leave the “prohibited place”.
The police document says the men, accompanied by a local priest, were permitted to enter the premises by a security guard, did not film inside and left when asked to do so.
Both left India before police began their enquiries. They are being investigated for trespassing and visa violations.
Two Indian journalists, D Anandhakumar and M Sriram, who had been assisting the French journalists with translation – but did not accompany them to Irel – were held by police for two days without explanation, and released after their detention became the subject of media enquiries. They have been asked to return to assist police with the investigation and fear they could be charged.