MADISON, Wis.—Police illegally videotaped a Wisconsin man having sex with his wife while she was in a coma in her nursing home room, an appeals court ruled Thursday.

David W. Johnson, 59, had an expectation to privacy when he visited his wife at Divine Savior Nursing Home in Portage, the District 4 Court of Appeals ruled. Therefore, police violated his Fourth Amendment rights against unreasonable searches when they installed a hidden video camera in the room, the court said.

“We are satisfied that Johnson’s expectation of privacy while visiting his wife in her nursing home room is one that society would recognize as reasonable,” a unanimous three-judge panel wrote.

The ruling means prosecutors cannot introduce the video tapes as evidence in their case against Johnson, who is charged with felony sexual assault for having intercourse with his wife without her consent at least three times in 2005.

Johnson’s wife, Leah, was admitted to the nursing home after suffering a stroke, unable to speak or sit up. Nursing home staff members fed, cleaned and turned her, checking on her at least every two hours. Prosecutors say she was comatose.

Johnson’s attorney Christopher Kelly said his client would visit the woman he married in 1988 every day, reading her the Bible and moving her arms and legs so her muscles wouldn’t atrophy. The woman’s sister, who is now her legal guardian, is upset that prosecutors brought charges against him, Kelly said.

“She believes her sister’s husband was merely expressing his love for his wife and was trying everything he could to bring her back to consciousness,” Kelly said.

But nursing home staff members feared she was in danger because they suspected he was forcing her to have sex and tipped off police. Police obtained a search warrant to videotape the room and installed the camera, which ran for three weeks. Johnson, who is free on bail, was charged based on that evidence in 2005.

Sauk County Circuit Judge Patrick Taggart, who heard the case out of Columbia County because of a request for a substitute judge, tossed out the videotape evidence last year, ruling it was an illegal search. Prosecutors appealed, arguing Johnson had a right to privacy when he visited his wife to care for her but not when he used the room for intercourse.

The appeals court affirmed Taggart’s ruling. Johnson believed he could spend time alone with his wife in private, was lawfully on the premises and took precautions to seek privacy such as closing the door, the court said.

The court rejected the prosecution’s argument that Johnson forfeited his right to privacy when he illegally had sex with his wife, noting proof of the assault “has not been admitted.”

“The salient inquiry is whether Johnson’s claim of privacy is consistent with historical notions of privacy involving a visit between spouses in a room in a nursing home,” the court wrote. “We conclude that it is.”

Department of Justice spokesman Bill Cosh said prosecutors are evaluating whether to ask the state Supreme Court to review the case.

Kelly said he believed prosecutors would be forced to drop the charges without the evidence on the tapes. He said the appeals court made “a pretty obvious call.”

“I think anybody who is visiting a spouse in a nursing home who is told, ‘you can have a private visit and we won’t disturb you,’ has reason to think he has privacy in the room,” he said.

If the case goes to trial, Kelly said he would argue that intercourse did not amount to sexual assault. Family members believe she “would be perfectly happy to feel the love of her husband in that situation,” he said.

Leah Johnson, 54, remains in a coma at the nursing home, he said. The couple did not have children.