Reliance Industries Ltd (RIL) chairman Mukesh Ambani and his family received death threats on Monday.
Three threat calls were received on a landline number at the Reliance Foundation Hospital in Mumbai's Girgaon this morning.
In a statement, the Mumbai Police said: "Reliance Foundation has filed a complaint about the threat calls to Reliance Industries chairman Mukesh Ambani and his family. More than three calls were received at the hospital. A probe is underway."
According to reports, a man was detained for his alleged connection to the threat calls. A preliminary investigation suggests the caller is mentally unstable.