India’s tax inspectors searched the office of British insurance giant Aviva’s life insurance unit near New Delhi last week and seized documents as part of an investigation into alleged tax evasion, sources familiar with the matter said.

Officers of India’s directorate-general of GST (Goods and Services Tax) Intelligence also seized laptops during their visit on November 7 and questioned some officials, including the India CEO Asit Rath and chief financial officer Sonali Athalye, said two of the three sources, who declined to be named due to the sensitivity of the matter.

Aviva Life Insurance, India, told Reuters: “We can confirm that GST officials visited our head office site, we are in full cooperation with them.” It shared no further details and declined to comment on its executives being questioned. The finance ministry, which controls the GST department, did not immediately respond to an email request for comment.

The Aviva searches are part of a broader investigation involving many insurers who face allegations of at least $610 million in unpaid dues, one of the sources, a senior Indian government official, said.

Companies allegedly accounted for sales commissions above the regulator-prescribed limit as advertising and marketing costs, and then claimed tax credits illegally, the source added.