New and disturbing allegations emerged Friday in the case of a Chinese-American couple accused of raising 21 children inside their Southern California mansion as part of an alleged surrogacy operation.

Guojun Xuan, 66, and Silvia Zhang, 39, allegedly maintained what prosecutors described as a “house of horrors” at their $4 million home in Arcadia, where they are accused of abusing children connected to the operation.

During a bail hearing, Los Angeles County Deputy District Attorney MacKenzie Teymouri told the court that the couple kept nearly two dozen children isolated from the outside world and prevented them from seeing sunlight, according to the Los Angeles Times.

“They didn’t go to school outside the home. They didn’t go to playgrounds. They didn’t go to restaurants,” Teymouri said. “They lived in this home and witnessed violence in the kitchen, in the bathrooms, in the bedrooms, in the foyer.”

Authorities also discovered the cremated remains of a surrogate child who died in Florida and whose remains had been shipped to the mansion, Teymouri said. The couple never opened the package and appeared “indifferent” to what happened to the child, she added, according to the Times.

Prosecutors said the children were expected to work for nearly 24 hours a day, studying “math, Mandarin and English.” They allegedly had to sit upright and pay attention or face beatings.

According to prosecutors, the children spent their days in “makeshift classrooms,” from early morning until night.

“From sunup, to sundown, these children, whether they’re in a high chair or old enough to sit at a desk, sat in what can only be described as makeshift classrooms,” Teymouri said, according to the Times.

The children had been confined indoors for so long that, after the Department of Children and Family Services removed them last year, they were reportedly “scared to go to the park because they hadn’t been outside,” Teymouri said.

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Prosecutors obtained video that allegedly shows Xuan shining a flashlight across sleeping children’s beds and beating any child who was awake. Teymouri said she had to mute portions of the footage because of the “constant screaming” in the background, which she attributed to repeated beatings.

Xuan faces charges of conspiracy to commit a crime, child abuse and accessory after the fact, as well as five counts of dissuading a witness.

Zhang has been charged with conspiracy to commit a crime and accessory after the fact, along with four counts of dissuading a witness.

Los Angeles County Superior Court Judge Caroline Lugo ordered the couple held in lieu of $20 million bail, agreeing with prosecutors that they posed a flight risk.

Teymouri also told the court that the couple helped their nanny, Chunmei Li, flee to China. Li had been charged with child abuse after allegedly striking a child so severely that the child was hospitalized with bleeding on the brain.

Mitchell Krems, Xuan’s attorney, argued that his client had no prior criminal convictions. He attributed the alleged abuse to nannies and said the couple had become targets of anti-Chinese sentiment in the United States.

Krems further argued that Xuan should be released because his health had deteriorated in custody. Xuan is undergoing leukemia treatment and is now permanently confined to a wheelchair, his attorney said.

Zhang’s attorney said the $20 million bail was excessive, pointing to what he described as the children’s luxurious living conditions.

“These kids, there was no cigarette burn marks. There was no cages. There was no dog collars. There was no abuse by belts. These kids were well nutritioned, they were getting education every day,” he said.