A Satyam insider blew the lid off the $1bn accounting fraud at Satyam which led its then chairman to admit to the crime in January.
Satyam was sold to Tech Mahindra this week after a battle to continue as a business after the fraud was announced. A government appointed board took over at Satyam
According to The Economic Times India a 14,000-page report by the Serious Fraud Investigation Office reveals that a former executive using a pseudonym sent an e-mail to a Satyam board member which quickly led to B Ramalinga Raju confessing.
Raju wrote a letter to the Satyam board in January admitting to falsifying the company's accounts for several years.
The sale to Tech Mahindra ended weeks of speculation but there will be continuing uncertainty for the buyer because the extent of the fraud is not yet clear and there are a number of legal challenges against Satyam.