A former Fort Riley soldier accused of sexually abusing a girl has been sentenced to 10 years in federal prison.

Fifty-two-year-old James Duke was sentenced Monday. He had pleaded guilty to one count of aggravated sexual abuse.

According to U.S. Attorney Barry Grissom, the investigation into Duke began in 2013 when the FBI discovered he was trading child pornography. Grissom said some of the photos were taken during the attacks on a girl authorities say Duke sexually abused while stationed at the military base.

Authorities said the abuse started when the girl was as young as 4 and occurred between October 1996 and October 2001.