An Oregon man has pleaded guilty to manslaughter and criminal mistreatment in the death of his 7-week-old son.

The Oregonian newspaper reports that 27-year-old Robert Ross Myers of Beaverton was sentenced to 20 years in prison after his plea was accepted Thursday.

Myers' son, Aden, died in January 2013. The state medical examiner says the cause was asphyxia from smothering and compression.

According to court records, Myers told police he smothered the baby by lying on top of him.