GRAND RAPIDS, Mich. (WOOD) — A former doctor at Michigan State University who also treated Olympic athletes has been indicted on federal child pornography charges.

Lawrence Gerard Nassar was charged Friday with one count each of possessing child pornography and receiving or trying to receive child pornography, according to the indictment.

The federal indictment states that Nassar received and attempted to receive at least six files or pictures of child pornography between Sept. 18, 2004 and Dec. 1, 2004.

The second count states that between Feb. 6, 2003 and Sept. 20 of this year, Nassar had computer discs or files that “contained thousands of images of child pornography,” including images involving a child under age 12.

Nassar faces a minimum of five years in prison and a maximum of 40 years. He also faces a lifetime supervised release after serving his time.

The charges were the result of a joint investigation by the FBI and the Michigan State University Police Department. The investigation is ongoing, anyone who has additional information about more potential victims in Michigan should call the Michigan State University Police at 944.996.7873. Information on other child porn or criminal sexual conduct Nassar may have committed outside Michigan should call the Detroit FBI Office at 313.965.2323.

Nassar is already facing three counts of criminal sexual conduct with a minor at the state level. He’s also been named in two civil lawsuits by former gymnasts who claim Nassar sexually abused them. Nassar has denied any wrongdoing.

NBC reports Nassar was fired from his sports medicine practice at MSU in September. He also served as a team physician for Holt High School gymnastics and Twistars Gymnastics Club.

Michigan Attorney General Bill Schuette previously said investigators are looking into more than 50 complaints against Nassar. Schuette also said the three state charges filed against Nassar were just the “tip of the iceberg.”