A care home in Iowa for people with intellectual disabilities subjected residents to "bizarre experiments" and used them as "human guinea pigs," according to a US justice department investigation.
The inquiry into the Glenwood Resource Center began last year following reports of an increased number of deaths.
Assistant Attorney General Eric Dreiband said: "Individuals with disabilities are not human guinea pigs, and like all persons, they should never be subject to bizarre and deviant pseudo-medical 'experiments' that injure them.
"Human experimentation is the hallmark of sick totalitarian states and has no place in the United States of America.”
The justice department concluded that experiments were conducted on residents without their consent.
One experiment involved reportedly overhydrating residents and caused physical harm. It said others involved psychological research on impulsivity.
Investigators found there had also been apparent plans by the former superintendent of the facility to conduct sexual arousal experiments using a computer containing images of nude and clothed children.
The justice department said it did not find evidence the images were ever shown to residents.
The former superintendent was fired last year about a month after the investigation began. Investigators also concluded that Glenwood's alleged use of restraints violated residents' rights.
The justice department report identified broad failings, including by the Iowa department of human services.
It said: "Iowa has been deliberately indifferent to those breakdowns and the risks they pose. "Glenwood frequently leaves residents at serious risk of harm or death by ignoring changes in condition outright, or by adopting a clinically unjustified 'wait and see' approach.”
The investigation concluded there was reasonable cause to believe the conditions at Glenwood violated the Fourteenth Amendment of the US Constitution.
It said that a teenage resident had been restrained 293 times over the course of less than two years.
Kim Reynolds, the Iowa governor, said: "What happened at the Glenwood Resource Center was unconscionable and unacceptable."