A former Kansas University worker faces up to 11 years in prison after several hundred images of child pornography were found on his work computer, said Charles Branson, Douglas County district attorney.

A tip to KU police was made in 2007 when someone reported that John G. Wallis, 62, Topeka, might have child pornography on his computer. Authorities conducted a search and found the images.

“They were found in the deleted spaces or the unallocated spaces of the computer,” Branson said.

Investigators also searched Wallis’ home computer but found no incriminating evidence.

Wallis worked as an electronics technologist in the physics and astronomy department, said Jill Jess, a KU spokeswoman. She said he was hired March 3, 1988, and terminated Sept. 13, 2007.

Charges were not filed right away, according to Branson, because the process of investigating the images can take time.

“Typically what happens with child pornography is it’s sent off to a national identification center to determine, in fact, if they have an identified victim in child pornography,” Branson said.

The children in the images that were found on Wallis’ computer were not local.

“In this type of situation, it’s child pornography that’s been downloaded over the Internet through different sharing sites,” Branson said.

In March 2009, Wallis was charged with sexual exploitation of a child. A preliminary hearing was held in June of this year. On Monday, he changed his plea to guilty. He remains out of jail at this time.

Branson said Wallis’ sentence will depend on his prior criminal history. He could receive probation or as much as or a little more than 11 years in prison. He also will have to register as a sex offender.

Sentencing is scheduled for Nov. 23.