PLEASANT HILL — Authorities have charged a Des Moines couple after their 16-year-old special needs son was found severely malnourished and zip-tied to a chair at the workplace of his mother.

That incident happened Feb. 22, when police responded to a call to a Pleasant Hill automotive store and found the boy zip-tied to a chair by his left ankle and through a belt loop on his pants, television station KCCI reported. Police said the teen weighed only 78 pounds at the time he was found.

An investigation found the boy was often denied food and locked in his room with no access to a bathroom, official said. Investigators say he was punished if he then urinated in his bed.

The punishment sometimes included beatings, officials said.

The boy’s parents, 48-year-old Jennifer Ryan and 47-year-old Richard Joe Ryan, have been charged with one count of first-degree kidnapping. They were booked into the Polk County Jail on Monday morning to await an initial court appearance.