Ajayi remains in jail after being previously charged with murder and kidnapping in the death of Lueck. He has not yet entered pleas to those counts.
A tech worker accused of killing a Utah college student was charged on Tuesday with 19 unrelated counts of sexual exploitation of a minor after investigators said they discovered child pornography on his computer.
Ayoola Ajayi, 31, had images of children as young as four years old, prosecutors said in charging documents.
Investigators took the computer as part of the investigation into the death of 23-year-old University of Utah student Mackenzie Lueck.
Ajayi remains in jail after being previously charged with murder and kidnapping in the death of Lueck. He has not yet entered pleas to those counts.
Police and prosecutors have not said how Ajayi and Lueck were connected or disclosed a motive for the killing, Daily Mail and Associated Press report.
A probable cause statement for the new charges doesn't indicate any link between the pornography and Lueck.
Lueck disappeared shortly after she returned from a trip to her California hometown for the funeral of her grandmother and took a Lyft from the airport to a park.
She exchanged text messages with Ajayi and met him at the park, apparently willingly, but her phone was turned off a minute after the final text and wasn't turned back on, prosecutors have said.
Police have said Lueck was last seen getting into Ajayi's car on June 17. She was reported missing three days later.