BOSTON (WHDH) -- A 56-year-old pediatrician at Children’s Hospital has been charged with receiving child pornography.

Dr. Richard Keller of Andover stood before a federal judge wearing a rumpled green T-shirt on Thursday. He is accused of buying and owning child pornography from a company operating online and outside the United States.

Court documents show he had films of children involved in sexually explicit conduct and owned more than 500 pictures and up to 100 DVD's, all sexually graphic.

Federal investigators alleged the pediatrician was buying from a company whose films showed mostly underage boys.

Officials at Children's Hospital released a statement that said:

“When the hospital learned of the allegations against Dr. Keller earlier today he was immediately put on administrative leave…No complaints or concerns have been expressed by any patients or family members about the care Dr Keller provided while he was at Children's.”

But, there were complaints when Keller's pregnant girlfriend was leaving court. She hid behind a piece of paper while his attorney protected her.

Neither one of them commented on the charges nor accusations that he spent close to $3,000 on pornography that was allegedly delivered to his on campus address at Phillips Academy where he was a medical director up until last year.

Phillips Academy said they are cooperating with the investigation.

Keller is now in federal marshals’ custody. They consider him a risk of flight.