MADISON, Wis. — When women at a group home for cognitively disabled elderly in Green Bay heard that the home’s old proprietor was moving back in, they were terrified. One swore to the home’s supervisor that she wouldn’t allow it: John, she said, was “dirty.”

“I don’t like what he does to us,” she said. Her housemate quickly shushed her, saying she wasn’t supposed to tell.

Police were called in but struggled to build a case against the man. The women — who had to be spoken to as if they were children — made accusations, recanted them and then made them again.

Many cases like this one in 2016 unfold every year across the nation, often going unresolved because of the special difficulties that make elderly people especially vulnerable to mistreatment or crime. Now Wisconsin is taking a radical step to curb abuse and get reliable evidence for prosecutions — handing out free surveillance cameras to family members so they can secretly record caregivers suspected of hurting their loved ones.

Attorney General Brad Schimel said it should make preying on the elderly harder to get away with. “Anybody caring for a senior probably should think if they’re misbehaving they could get caught for it,” he said.

But Wisconsin’s program, only the second of its kind, is prompting protests by the elderly care industry and privacy advocates who consider it a disturbing government foray into private spying.

“Now people are recording stuff for the cops,” said Lee Tien, senior staff attorney for the Electronic Frontier Foundation, a nonprofit organization that works to protect privacy as technology evolves. “There’s no oversight or governance. (The programs) definitely create concern about expansion of government surveillance into private spaces.”

Schimel noted that the cameras are loaned for only 30 days, and that people could already place a camera if they suspected abuse. Agency officials have spent $1,200 on equipment to start the program on a pilot basis.

Elder abuse can include beatings, molestation, theft of jewelry or credit cards and neglect. Victims with dementia or other cognitive problems often don’t realize they’ve been victimized or struggle to report incidents coherently.

National statistics are difficult to compile, but state data suggest a worsening problem. In Wisconsin, counties reported 7,019 complaints in 2016, up 21 percent from just three years earlier. Demographics are broadening the vulnerable population, with the number of people 65 and older projected to almost double by 2050 in the U.S.

The National Association of Attorneys General called on its members in August to focus on elder abuse.

At least six states — Texas, Oklahoma, New Mexico, Washington, Illinois and Maryland — have passed laws allowing some form of surveillance in nursing homes. One, New Jersey, has also begun loaning cameras.

Making video recordings in both New Jersey and Wisconsin is legal as long as at least one party involved is aware it’s happening. Camera borrowers must agree not to make audio recordings to avoid violating federal wiretap laws, and agree not to place cameras in bathrooms or the caregiver’s bedroom.

Neither program has generated any criminal charges yet, but they have generated vocal opposition.

Jon Dolan, CEO of Health Care Association of New Jersey, which represents long-term care facility providers, said the cameras could capture residents in compromising positions, like being naked while a nurse works on them.

The Wisconsin Personal Services Association, a statewide coalition of home care providers, foresees a chilling effect on recruiting caregivers for jobs that are already difficult and low-paying.

“Basically the worker has a privacy interest that doesn’t seem to have been considered,” said Tien of the Electronic Frontier Foundation.

Other states are looking at Wisconsin and New Jersey’s loaner programs. The results of some private surveillance efforts have provided encouragement.

In suburban Milwaukee, a $650 private camera system installed by James Bira caught a caregiver emptying his mother’s liquor cabinet. He paid for the cameras out of his own pocket, mounted them in plain sight and warned caregivers, but it didn’t deter the liquor thief.

“I’ve had a couple [of] caretakers who didn’t like (the cameras), but I said that’s the way it’s going to be,” Bira said. “I’m going to protect my mom.”

In the Green Bay case, investigators ultimately won a sexual assault conviction against the group-home proprietor but it was difficult — without any physical evidence, investigators had only the women’s statements to go on.

“If we would have had the video,” said Brown County Sheriff’s Sgt. Tim Bernklau, “it would have been a slam-dunk.”