The 75-year-old has been a driving influence in her once-dominant party since the 1991 assassination of her husband, former prime minister Rajiv Gandhi, and heir to a political dynasty that stretches back to the country’s independence from Britain.

Authorities are probing a decade-old complaint filed by a lawmaker from the ruling Bharatiya Janata Party (BJP), who accused her family of misusing Congress funds to buy a now-defunct newspaper business and personally acquire its highly valuable property portfolio.