YAMHILL, Ore. (KOIN 6) — Foster parents of two young children were arrested and charged with first degree assault and criminal mistreatment in Yamhill County.

Danielle Yvonne Yates and John Henry Yates were arrested around 6 p.m. Wednesday, the Yamhill County Sheriff’s Office said.

The children, a 4-year-old boy and a 5-year-old girl, lived with the Yates’ for about four years, officials said. The couple were the legal guardians of the children.

But an investigation by the county’s Special Investigations Unit led authorities to conclude the couple was not providing adequate food or medical care to the children.  Officials said a relative noticed the condition around Christmas, and the children spent about a week in the hospital during the holidays.

“Nothing we do is more important than protecting children,” DHS Child Welfare Director Lois Ann Day said in a statement. “When we see reports of injuries to children known to the agency, and when those injuries have been caused by abuse or neglect, we must respond quickly. Therefore I am announcing an immediate review of this case, which will be conducted in the next 24 hours, to look into the decisions and actions taken by DHS staff in Salem and in county offices.”

The 31-year-old woman and 42-year-old man are held in the Yamhill County Jail with bail set at $350,000 each.