Lana Clayton "accidentally" shot her husband with a crossbow. Two years later he was dead.

Steven and Lana Sue Clayton seemed like they had the perfect marriage.

The church-going South Carolina residents gave their neighbours no reason to be concerned.

The couple had been together for eight years. Steven was known for his “big personality” and Lana Sue regularly attended a local bible study group.

When Lana Sue, now 52, shot Steven in the head with a crossbow as he slept, it was very quickly brushed off as an accident and Steven went on to make a full recovery.

Lana Sue told detectives she had been downstairs trying to “load a crossbow” and was having difficulty with it. She then went upstairs to get her husband to help and found him sleeping. Lana Sue claimed that when she turned to leave the room, the crossbow accidentally went off.

As The Herald reports, Steven would later tell detectives he “did not believe his wife was trying to kill him”. One year after the shooting, detectives officially ruled it an “accident” and “no intent to commit a crime was found”.

Two years later, Steven was dead.

On July 21, 2018, the 64-year-old was found dead in the couple’s lakefront mansion on Island Forks Road.

According to the New York Post, Lana Sue, a registered nurse, told authorities she had found her husband lying face down at the foot of the stairs. She said he had been suffering vertigo for days.

Most people immediately believed Lana Sue’s story. Her family and friends gathered around to support the grieving widow and a funeral was held in the backyard of the wealthy couple’s enormous estate.

The police, however, weren’t so quick to believe Lana Sue.

While the widow put on a public display of grief, the police were quietly investigating the couple’s relationship behind the scenes.

Last week, they got a break in the case.

The toxicology reports had come back with an unusual result, Steven’s blood contained fatal levels of tetrahydrozoline.

Tetrahydrozoline is found in over-the-counter eyedrops and nasal sprays. If taken orally, the chemical can cause seizures, stop breathing and induce comas.

According to the Charlotte Observer, when police confronted Lana Sue with the report she confessed to killing her husband.

On Friday, she was arrested and charged with homicide and malicious tampering of food.

“We are making a comprehensive review of all events in the relationship between the defendant and the victim,” said Kevin Brackett, 16th Circuit solicitor, during a press conference.

“We will be taking a look at the relationship and the 2016 incident.”

In the upcoming court case, prosecutors will allege Lana Sue poisoned Steven’s water with tetrahydrozoline over a three day period.

If found guilty, Lana Sue will face the death penalty.

The couple’s neighbours are still processing the unexpected turn of events.

“I am just stunned,” Ken Sanford, who knew them both, told The Herald.

“She seemed like a sweet lady,” Sanford said. “Steven was very proud of her accomplishments.”