The plywood box where three children, aged 11,13 and 14, were found living.

A United States couple were arrested Friday (NZT) after allegedly keeping their three children locked in a box for four years, authorities said.

San Bernardino County deputies found the children, aged 11,13 and 14, in a plywood box with no electricity or running water on Sun Fair Road in Joshua Tree, California, according to the Sheriff's Department. Authorities said the box was 6 metres long, 3 metres wide and 1.2 metres high (20 feet long, 10 feet wide and 4 feet high).

Authorities found mounds of trash and human faeces throughout the property. Between 30 and 40 cats were roaming freely and inside a travel trailer on the property.

The children did not have enough food and were living in an "unsuitable and unsafe" environment, the Sheriff's Department said.

The children's parents, Mona Kirk and Daniel Panico, were arrested on suspicion of willful cruelty to a child.

They were each being held in lieu of US$100,000 bail.

- Los Angeles Times​