India, Sept. 20 -- Court transcript details undercover operation, digital records, payments and sentencing incentives.

The question that has remained unanswered since Nikhil Gupta pleaded guilty in the United States in February is what made him abandon a long-running fight against the murder-for-hire charges in the Gurpatwant Singh Pannun assassination case and accept a potential sentence of more than two decades in prison.

The full transcript of Gupta's February 13 guiltyplea hearing now provides an important indication of what his defence team was up against. In laying out the case it would have presented to a jury, the US prosecution cited an undercover operation, a confidential source, a post-arrest statement by Gupta, WhatsApp mess...