Royal Philips (NYSE:PHG) reportedly fired a whistleblower in 2011 after he warned about suspicious sales of medical equipment to the Brazilian government.

Brazilian prosecutors claimed the Amsterdam-based company, among others, was part of an international health-care cartel last year. Jose Israel Masiero Filho informed Philips of his suspicions of illegal activity as far back as 2010, according to Reuters.

Masiero’s claims reached several senior executives at Philips, including then-CEO CEO Steve Rusckowski (now chief executive at Quest Diagnostics (NYSE:DGX)).  However, the company continued to sell to a Brazilian middleman who held contracts with the Brazilian Ministry of Health. Allegations in the ongoing graft probe include Masiero’s suspicions that payoffs were made to land that government business.

Philips told the wire service that it’s cooperating with Brazilian authorities during the ongoing investigation. The U.S. has also launched probes as the investigation widens.

Other big names allegedly involved in the graft are General Electric (NYSE:GE), Johnson & Johnson (NYSE:JNJ) and Siemens Healthineers (NYSE:SI). All three have previously denied wrongdoing, the news service reported.