A retired brigadier general living in Pennsylvania was charged with 15 counts of child pornography, authorities announced Wednesday.

Retired U.S. Air Force Brig. Gen. Frank Sullivan was charged after a search of his home in Mechanicsburg, about eight miles west of Harrisburg, turned up computers "replete with thousands of searches for "'preteen' images" and pictures of children “engaged in very graphic sexual acts," the Pennsylvania Attorney General's Office said in a statement.

Sullivan was arrested Wednesday in Cumberland County and charged with 15 felony counts of sexual abuse of children and one count of criminal use of a communication facility.

He pleaded not guilty at an arraignment and his bail was set at $100,000 unsecured bond.

Sullivan is the former executive director of the Pennsylvania Military Community Enhancement Commission and completed tours of duty in Iraq and Afghanistan, the statement said.

Retired U.S. Air Force Brig. Gen. Frank Sullivan. Pa. Attorney General's Office

“General Sullivan’s alleged actions disgrace his work and besmirch the Pennsylvania National Guard, an organization that has bravely and dutifully come to the aid of Pennsylvanians whenever they have been called,” Attorney General Josh Shapiro said.

Shapiro said agents from his office discovered Sullivan’s penchant for viewing images of preteen children during an investigation on a file sharing network.

An October search of Sullivan’s home revealed a desktop and a laptop that were filled with searches and images of preteen children, according to the state attorney general's office.

A computer forensic analysis also identified 37 search terms commonly used by people looking for child pornography on Sullivan's laptop.

The Pennsylvania Attorney General's Child Predator Unit also arrested one of Sullivan's tenants in October, Bobby Glenn Williams Jr., and charged him with 14 felony counts of disseminating photos of child sex acts, 11 felony counts of child pornography, and one felony count of criminal use of a communication facility. Williams was renting a room in Sullivan’s home, according to authorities.

His attorney, Patrick Lauer, told NBC News the charges were waived to a higher court during a preliminary hearing that was also on Wednesday.

"There were four people living in that house, one person whose room was searched," Lauer said Wednesday. "That person had child porn all over that computer."

Lauer said he did not know how much access Sullivan's tenants had to the other computers in the house.

A formal arraignment is scheduled for Jan. 23, 2020.