On arriving at the middle-class bungalow in Perris, a town of 70,000 situated 15 miles outside Riverside, they found the children kept in dark, squalid and stench-filled conditions. Some were shackled to their beds.

Many appeared far younger than their age because of the horrific conditions they appear to have been kept in, according to officials investigating the case.

The children are now being treated for malnutrition.

Mother 'perplexed' by police involvement

Greg Fellows, Riverside County sheriff's captain, revealed that Mrs Turpin had appeared "perplexed" as to why police were present at her home.

"The conditions were horrific," he said.

The children are all believed to be the Turpins' biological offspring, authorities said.

Mr Fellows said the investigation has so far found no indication of sexual abuse but that the conditions amounted to torture.

"If you can imagine being a 10-year-old and being chained to a bed ... I would call that torture," he said.

Mr Fellows praised the "bravery" of the teenager who managed to flee the house of horrors "through a window".