A South Carolina woman is accused of fatally poisoning her husband in a case that has shocked the couple’s neighbors and friends, The Herald reports.

When 64-year-old Stephen Clayton died on July 21, he was found in his home’s foyer in what looked like a fall down the stairs.

But a toxicology screening later detected fatal levels of tetrahydrozoline – a chemical in nasal sprays and eye drops – in his system.

His wife, 52-year-old Lana Sue Clayton, has admitted to investigators that she put the chemical in her husband’s water without his knowledge between July 19 and July 31.

The couple had reportedly been married for eight years and lived in an $822,000 home modeled after George Washington’s Mount Vernon residence.

Stephen Clayton’s funeral was held at the house in August before authorities had ascertained how he died.

Prosecutors have charged Lana Sue Clayton with murder and malicious tampering of food. She is being held in the York County Detention Center.

Her Facebook page indicates she worked in nursing care for the U.S. Department of Veterans Affairs in Charlotte, North Carolina.

Neighbors told WSOC-TV that Lana Sue Clayton was a regular at a local Bible study session.

Deborah Pollard, who lived near the couple, said she was dumbstruck by the news of the poisoning.

“It just makes no sense,” Pollard said.

Stephen Clayton was a retired business owner who founded and operated the company Physical Therapy Resources. Those close to him say he was a generous person who mentored kids and supported good causes.

Ken Sanford, a friend of the couple, told the newspaper that Lana Clayton “seemed like a sweet lady.”

“I am just stunned,” Sanford said.