Calif. Couple Arrested for Alleged Child Abuse — Now 21 Children are in Protective Custody

21 children – some of whom were birthed by surrogate mothers – were placed in protective custody amid an investigation involving allegations of child abuse and child neglect.

The case came to light on May 7 when officers with the Arcadia Police Department learned that a two-month-old boy was admitted to the hospital with a traumatic head injury and intracranial bleeding.

Police traced the infant to a multi-million-dollar home in the 600 block of West Camino Real Avenue in Arcadia. Inside the home, police allegedly found 15 children between the ages of two months and 13-years-old.

There were at least six nannies taking care of the children at the residence when officers arrived.

“The home was set up to basically homeschool the younger children,” Arcadia Police Lt. Kollin Cieadlo tells PEOPLE. “There were classroom settings and there were areas for the children to play and eat and things like that. It was very much focused on education. It appeared that a lot of time was spent as a group with all the children and the nannies going through education type materials.”

Officers found an additional six children they say are related to the investigation at other residences within Los Angeles County.

“The majority of the kids were probably within the one- to three-year age range,” Cieadlo says.

Police obtained surveillance footage which allegedly showed one of the nannies — employed by the child’s parents Silvia Zhang, 38, and 65-year-old Guojun Xuan — “violently” shaking and striking the two-month-old boy on May 5, per an Arcadia Police Department press release.

Police said the infant wasn’t transported to the hospital for another two days.

The couple was arrested on charges of felony child endangerment/neglect and booked at the Arcadia Police Department Jail. They’ve since been released on bail.

An arrest warrant has also been issued for the 56-year-old nanny Chunmei Li though her whereabouts remain unknown, per the press release.

Investigators believe that some of the children were born through surrogacy.

“Silvia was able to produce birth certificates showing her as the mother for the children,” says Cieadlo. “We don’t believe that she birthed all these children, the age range would make it impossible. There’s just too many and too close in age for her to have done that. We do know that at least a few of the children were born through surrogacy.”

Cieadlo says the couple ran a surrogacy business.

“We were aware that they were running a surrogacy business, but we don’t know the extent of that,” he alleges, adding that the priority and focus right now is related to the child abuse side of things.

“It’s almost like a two-phase investigation,” he says. “The first phase is securing charges. And then the second phase is going to be looking at kind of where the surrogacy business takes us. We’re going to be working with the feds on that side of it.”

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Kallie Fell, executive director for the Center for Bioethics & Culture, tells PEOPLE she has been working with a Texas woman named Kayla, who was allegedly hired by the couple as a surrogate. Fell claims that Kayla was not the only surrogate hired for the intended parents.

“Halfway through her pregnancy, other women reached out… and they started talking, and they found out that there were many different women who were pregnant at the same time as Kayla with a baby for the same intended parents… and then not only that, but one of the babies had been harmed by a nanny and Child Protective Services was involved.”

Fell says Kayla is currently seeking to get custody of the baby she gave birth to on March 13.

“It was something I never would have expected to happen—something almost unbelievable unless you’re living it,” Kayla told KTLA5.

“It’s a very unique case that myself and our agency has not dealt with in the past,” says Cieadlo. “We handle child abuse cases regularly but this, with the sheer volume and the number of children present, it is definitely a unique situation that is an in depth and involved case that’s going to take some time to get to the bottom of.”

The couple could not immediately be reached for PEOPLE’s request for comment.