A world-renowned Harvard University child psychiatrist and two of his colleagues failed to declare millions of dollars in consulting fees from drug manufacturers to university officials, an investigation by Sen. Charles Grassley’s staff revealed.

Dr. Joseph Biederman, known worldwide for his work in researching antipsychotic medicines for children, did not tell the university that he had earned at least $1.6 million from pharmaceutical companies that make them.

Also, his colleagues, Dr. Timothy E. Wilens and Dr. Thomas Spenser had earned $1.6 million and $1 million respectively, which they did not declare as well, thus breaking federal and academic regulations, which are in place to monitor possible conflict of interest, Sen. Grassley said, according to the New York Times. The newspaper reported the investigation’s findings on Sunday. Senator Grassley is calling for a national reporting system in which drug companies disclose payments to doctors.

The relationship between the Harvard academics and drug companies is highly controversial, as their research has advocated the use of previously unapproved psychiatric medicines in children. Following Sen. Grassley’s investigation, Harvard University officials began investigating themselves the academics’ outside earnings. Alyssa Kneller, a Harvard representative released a statement saying, “each doctor may have failed to disclose outside information…that should have been referred.”

Neither Dr. Biederman, nor his colleagues commented on the results of the investigation.