ST. CHARLES, Mo. (AP) — A trial is underway in eastern Missouri for a couple accused of keeping their autistic son in a makeshift cage.

Jury selection began Tuesday in St. Charles County felony child-endangerment trial of 45-year-old Terry Smith and his 44-year-old wife, Victoria Smith.

Both have pleaded not guilty to the charges filed two years ago.

A prosecutor has said an anonymous call tipped authorities in December 2010, when the boy was 6.

When police, paramedics and a case worker responded, the boy’s grandmother was watching him and five siblings. Authorities say she led them to the basement, where the autistic child was in a 3-foot-by-6-foot crib covered with a plywood top and held together with bungee cords and zip ties.

Investigators said he was naked and sitting in feces and urine.