A Texas husband and wife arrested by US federal authorities for allegedly forcing a 38-year-old Nigerian national to care for their five children over a two-year-period and never paying her face up to 20 years in federal prison.

A statement from the Federal Bureau of Investigation alleges that Chudy and Sandra Nsobundu, 56 and 50, respectively, were detained on Monday on charges of forced labor, withholding documents, conspiracy to harbor an illegal immigrant and visa fraud.

Investigators contend the Nsobundus held the woman captive for two years and even seized her passport, preventing her from leaving the country.

The couple allegedly abused the woman physically and verbally, forcing her to clean, cook, and care for their children from 5:30 a.m. until 1 a.m.

The couple “regularly referred to the victim as ‘the idiot’,” according to an FBI statement, and also told the woman “she could not watch television or even sit down during her work hours. She was also allegedly told to sleep on the floor and could not use warm water to bathe or wash her hair.”

Authorities also claim “she was not allowed to eat fresh food and was only permitted the leftovers from the previous prepared meals,” and that “if the victim even wanted some milk for her tea, she would have to actually strain the milk out of the children’s cereal bowls.”

The woman mostly spent her days inside the Nsobundus’ home and was allowed out only for short walks, investigators allege.

The couple never made good on their promise to pay the woman $100 a month for her services, according to the FBI.

If convicted of forced labor, the Nsobundus face up to 20 years in federal prison. Visa fraud carries a maximum penalty of 25 years while the withholding documents and harboring conspiracy charges carry a maximum five and 10 years, respectively.

All of the charges could also result in a $250,000 in fines.

It was unclear Wednesday whether the Chudy Nsobundu had legal representation. Joan Nwuli, Sandra Nsobundu’s attorney, was unavailable for comment Wednesday.

•Adapted from a story by PEOPLE. Photo shows the accused couple, Chudy and Sandra Nsobundu.