(CNN) When Kimberly Milligan moved into her California home in 2015, she was told her grandson might soon have a playmate, since a family of 12 lived across the street.

But Milligan never saw children scampering in the backyard, never heard playful screams.

A few times, Milligan saw a woman across the street with an infant cradled in her arms. She occasionally noticed three other children, who looked like they were 14 years old or younger.

Milligan and her neighbors in the quiet, nondescript suburban Perris neighborhood said they were shocked to learn that DavidAllen Turpin, 56, and his wife, Louise Anna Turpin, 49, are accused of holding their 13 children captive . Authorities said some of the children were shackled to beds with chains and padlocks.

"I'm devastated. It's so close to home -- literally," Milligan told CNN Tuesday.

Early Sunday, the Turpins' 17-year-old daughter climbed out of the house through a window and called 911 from a deactivated cell phone she found in the home, the Riverside County Sheriff's Department said.

David Allen Turpin and Louise Anna Turpin.

The teenager, who authorities said "appeared to be only 10 years old and slightly emaciated," told officers her 12 siblings were being held against their will.

Sheriff's deputies went to the home on Sunday and found the 12 victims who "appeared malnourished and very dirty." Several children were shackled to their beds "in dark and foul-smelling surroundings," the sheriff's department said.

Authorities arrested the couple that day on torture and child endangerment charges. The victims range in age from 2 to 29.

The suspects are being held in the Robert Presley Detention Center, each on $9 million bail, the sheriff's department said Monday. The couple is scheduled to appear in court on Thursday, according to online records.

One neighbor told CNN affiliate KABC that she saw the parents being arrested early Sunday. The children were taken from the home in their pajamas, she said.

"They were very, very pale-skinned, almost like they've never seen the sun," said the neighbor, who did not wish to be identified.

"And it was mostly girls ... kind of small-framed," the neighbor said.

Jennifer Luna, another neighbor, shook her head in astonishment.

"It's so sad, so horrible," Luna told CNN affiliate KCAL/KCBS. "I can't believe this. I can't believe this."

The adult children are being treated at Corona Regional Medical Center in Corona, and the six minor children are at Riverside University Health System Medical Center in Moreno Valley.

David and Louise Turpin in a family photo.

'They froze'

Milligan was surprised to learn that the three children she believed to be adolescents were actually adults.

"I thought they were like 12, because they looked so malnourished, so pale," Milligan told KCAL/KCBS.

One encounter with them stood out to her in particular.

She and her son had finished putting up their Christmas decorations, when they noticed the three children across the street putting up a Nativity scene in front of their house. The Milligans walked over to compliment the children on the decorations.

"They froze," Milligan said. "They immediately shut down."

They seemed "scared to death," she said. "You could tell they were terrified."

David and Louise Turpin and their children.

Milligan said the children seemed to be on the defensive, "where they're trying to deter a threat, where they were like 'I'm invisible. You can't see me.'"

She and her son tried to reassure the children that they were neighbors from across the street.

"We're not trying to harm you. ... We just wanted to talk about your Christmas decorations," Milligan recalled them saying.

But the Turpin children stayed frozen.

"They didn't utter one word," Mulligan said.

Milligan said she never saw the Turpin kids decorating outside again.

CORRECTION: This story has been updated to correct the age of David Turpin. He is 56.