General counsel at companies that do business with the federal government might want to take note of thousands of whistles that were handed out in Washington, D.C., on Monday along with the moving billboards on trucks that drove around government buildings for hours.

The whistles and billboards announced the launch of Whistleblower Aid, a nonprofit, nonpartisan law firm that seeks to offer free advice to federal employees who wish to expose government wrongdoing, including accepting bribes or kickbacks on contracts.