Duncan, 29, Joplin, entered an Alford plea meaning he does not admit guilt, but acknowledged the prosecution has enough evidence that a conviction would be likely if the case went to trial.
Under the terms of the plea agreement, one count of child abuse was dismissed.
Duncan's crime was described in the probable cause statement:
While living with his girlfriend, Haley Simpson, Adam Duncan spanked Simpson's four-year-old son as punishment for failing to use the toilet.
During this time, Simpson and Duncan both spanked (the child) with a bare hand to (the child's) bare skin. (The child) suffered finger-shaped bruises to his buttocks and waistline from the spankings.
Further, on December 5, 2018, Adam Duncan committed the crime of abuse of a child. During this instance, Duncan physically struck (the child's) head with his hand multiple times causing serious bleeding to the right side of his head. (The child) also had serious bruising to the back of his hands and thighs caused by physical abuse.
Duncan's girlfriend, Haley Simpson, pleaded guilty March 27 to an amended charge of endangering the welfare of a child and was placed on unsupervised probation for two years.