Sixteen children from the same family were rescued from a dilapidated home in rural Ohio after investigators said they were living in “deplorable” conditions, including human waste in and around the residence and confinement to a small space for much of the past four years.

Ohio officials said the children—ranging in age from about 18 months to 18 years—were reportedly not enrolled in school. They described some children as unable to speak or with limited communication, and said an 18-year-old developmentally disabled child could not even write her name.

Investigators came across the family during the execution of a search warrant tied to a separate investigation. Vinton County Sheriff Ryan Cain said the conditions were worse than those for the family’s livestock, and described the scene as disgusting. Ohio Attorney General Andy Wilson said the home was among the worst he had ever encountered, calling it “pure evil.”

The children were taken into temporary custody of the Ohio Department of Jobs and Family Services, with some transported to hospitals in Columbus and others flown by helicopter. Officials said one child was in critical condition when discovered and others were admitted for treatment.

Four adults—identified as Gary Siders Jr., Gary Siders Sr., Christina Siders and Elizabeth Siders—were charged with felony child endangerment. Prosecutors said the charge reflects serious physical harm. Court records indicated not-guilty pleas were entered and bond was set at $300,000 for each defendant, with restrictions including orders barring contact with one another or the children.

Authorities said it appears the family had moved around southern Ohio over the years and that it seemed as if outsiders were unaware of the children. Neighbors told reporters they had not seen children and described the area as quiet, while investigators said they are reviewing whether the family had been reported to children’s services agencies.

The case is the latest in a line of high-profile family abuse matters, with officials drawing comparisons to prior incidents involving yearslong abuse behind closed doors.