A 21-year-old man who admitted sexually abusing a horse in a Hillsboro-area barn last April was sentenced Friday to a year and eight months in prison.

Kenneth L. Duyck pleaded guilty the same day in Washington County Circuit Court to sexual assault of an animal, unauthorized use of a vehicle and second-degree burglary. He admitted to abusing Ellie the horse on April 18, stealing a pickup from another barn in Forest Grove sometime the next week while released from jail, and then breaking into the Forest Grove Storage Lot on May 2, court records show.

A judge banned Duyck from owning any horses or domestic animals for 15 years. Duyck must also register as a sex offender and participate in sex offender and mental health treatment programs. The judge also ordered Duyck not to contact his victims and revoked Duyck's license for one year.

Duyck, who has been diagnosed with autism spectrum disorder and attention deficit hyperactivity disorder, was at one point ordered by a judge to obtain a mental health evaluation at the Oregon State Hospital, court records show.

According to a psychological evaluation report, the Hillsboro-area property owner told county deputies she found one of her horses tied up in a stall on April 19 different from the way she left the animal and later found semen on its genitals. She recalled someone who gave his last name as Duyck had called her the day before, asking if he could sleep on her property and she said no. She thought the incidents may been related.

A neighbor described a man who gave the same name asking for work earlier that day. A former employer linked Kenneth Duyck to the incidents, the report said.

Duyck was found sleeping in the stolen pickup on April 24. He admitted to a detective that he called the Hillsboro-area stable during the day and requested to sleep there. Despite being rejected, he went there anyway at night while out on a walk, the report said.

Duyck said he went to the stable, tied up a horse with a rope and planned to groom it, but instead claimed he ejaculated on the horse’s tail, according to the report.

Duyck said he hadn’t been taking his medication for more than a month at the time and “made a bad decision,” the report said.

Police later linked the DNA evidence collected by the horse's owner to Duyck.

-- Everton Bailey Jr.

ebailey@oregonian.com | 503-221-8343 |@EvertonBailey

Visit subscription.oregonlive.com/newsletters to get Oregonian/OregonLive journalism delivered to your email inbox.