Authorities in India are investigating the disappearance of up to $100 million in stock receipts from scandal-plagued outsourcer Satyam's accounts.

Investigators from the country's Serious Fraud Investigation Officer contend that Satyam sold $150 million in American depository receipts through the New York Stock Exchange but only $50 million was deposited into the company's accounts.

Satyam was first listed on the NYSE in 2001.

If confirmed, the theft would add considerably to the already lengthy list of misdeeds that occurred under the watch of former Satyam chairman Ramilinga Raju.

Raju, along with his alleged accomplices, created a complex system of business applications in order to generate thousands of fake invoices that were used to falsely inflate Satyam's revenue by more than $900 million, investigators have said.

To carry out the scheme, the perpetrators rigged accounting systems so that users could create fake documents that wouldn't be detected by Satyam's legitimate business applications, according to India's Central Bureau of Investigation. They also allegedly used a modified version of Microsoft Excel linked to an Inventory Management System to bypass Satyam's accounting controls.

All told, Raju and his cohorts -- including, allegedly, two employees of Satyam auditor PricewaterhouseCoopers India -- used the setup to create 7,561 phony invoices purportedly worth $946 million. CBI investigators engaged forensic computer analysts to help uncover the scheme.

Raju was arrested and jailed earlier this year for his role in the scandal. Telecom outsourcer Tech Mahindra has agreed to acquire Satyam for $422 million in an effort to give the company a fresh start.

Last week, Raju's attorneys claimed he's suffering from cardiac problems that render him unfit to take lie-detector tests that authorities hope will help them uncover more details of the fraud.

Raju's legal reps made the claim in responding to the CBI's request that Raju make himself available for polygraph testing.