India’s market regulator is investigating Adani Group’s links to some of the investors in the conglomerate’s aborted Rs 20,000 crore follow-on public offer, two sources said, amid growing concern in New Delhi about a US short-seller’s allegations against one of the country’s top industrial groups.

The Securities and Exchange Board of India (Sebi) is looking into any potential violation of Indian securities laws or any conflict of interest in the share sale process, said the two sources who have direct knowledge of the matter.

The watchdog is investigating relationships between Adani and at least two Mauritius-based firms — Great International Tusker Fund and Ayushmat Ltd. — which participated as anchor investors, among others, said the sources, who spoke on the condition of anonymity due to the confidential nature of the probe.

Under India’s capital and disclosure requirement rules, any entity related to a company’s founder or the founder group is ineligible to apply under the anchor investor category. One of the sources said the focus of the probe would be whether any of the anchor investors are “connected” to the founder group.

Sebi and Adani Group did not respond to requests for comment about the investigation. Great International Tusker Fund and Ayushmat Ltd also did not respond to requests for comment.