Thousands of companies that cashed in on President Barack Obama's economic stimulus package owed the government millions in unpaid taxes, congressional investigators have found.

The Government Accountability Office, in a report being released Tuesday, said at least 3,700 government contractors and nonprofit organizations that received more than $24 billion from the stimulus effort owed $757 million in back taxes as of Sept. 30, 2009, the end of the budget year.

Click here to read more.