A 67-year-old Casper man pleaded guilty Thursday to charges of sexually abusing a child who was under the age of 10.

Larry Richard Osborne faces up to 15 years behind bars when he is sentenced in Natrona County District Court.

In exchange for him pleading guilty to one count of third degree sexual abuse of a minor, prosecutors dropped three other charges alleging sexual abuse against the same underage victim.

Judge Scott Skavdahl accepted the plea Thursday morning.

Osborne initially pleaded not guilty to all four charges in August, but changed his plea after reaching an agreement with prosecutors.

After the plea was entered Thursday, District Attorney Michael Blonigen said the victim's parents were aware of the deal and approved of it. They did not want the victim to have to testify about the abuse, he said.

Police arrested Osborne in summer 2008 after learning of the allegations from the victim's father. The victim told authorities the abuse had occurred numerous times during the previous three or four years, according to a police affidavit.

The last incident, in July 2008, took place while another child was in the room and while the Disney show "Phineas and Ferb" was on the television, according to police.

The Star-Tribune does not identify victims of sex crimes.

Osborne, who is awaiting sentencing, remains free on $20,000 bond.

Reach crime reporter William Browning at (307) 266-0534 or at william.browning@trib.com.