KELSO, Wash. -

A Superior Court judge has convicted a Longview, Wash., couple of withholding food from two of their five adopted children, making them resort to eating dog food.

Cowlitz County Judge Michael Evans ruled Tuesday that Jeffrey and Rebecca Trebilcock starved their then-13-year-old adopted son nearly to death and denied a significant amount of food to his biological sister. The girl was 12 when she and her adopted siblings were seized by the state last year.

The boy weighed only 50 pounds -- half the normal weight for his age -- when he and four adopted sisters were placed in protective custody.

According to reports, the couple was convicted of first-degree criminal mistreatment of the boy and third-degree criminal mistreatment of his sister.

Prosecutor James Smith said they face four to five years in prison at sentencing Aug. 23.

The boy testified that he wasn't allowed to use the bathroom at night, so he urinated in a cup. If his parents found the cup, they made him drink it. He also said

The prosecution alleged the couple also denied food to three other adopted girls. However the judge acquitted the Trebilcocks of those charges.

All five of the children are now in foster homes.

The couple declined comment.