Investigators in South Carolina said they charged a woman with murder after she admitted to poisoning her husband, but WSOC-TV has learned that officials believe this may not have been the first time she tried to kill him.

>> Watch the news report here

According to officials, Lana Sue Clayton shot her husband in the head in 2016 with a crossbow while he slept. Officers told WSOC that at the time, both she and her husband told deputies it was an accident, and no intent to commit a crime was found.

Officials said Clayton's husband, Stephen, died July 21 from poisoning.

>> On WSOCTV.com: Police: Wife accused of poisoning husband with eye drops may have tried to kill him before

Authorities said toxicology tests found poisonous levels of tetrahydrozoline in the body of the victim, which is the chemical found in eye drops.

According to officials, the crime took place at the couple’s home on Island Forks Road in Clover.

"It just makes no sense,” said Deborah Pollard, who lives nearby.

Lana Clayton was booked into the York County Detention Center.

"Somebody does something like that? That's crazy,” said neighbor Sean Magan.

Neighbors told WSOC that the Claytons were married for eight years.

One woman said Lana attended a neighborhood Bible study, and Stephen was known for his big personality.

Neighbors said his funeral was held earlier this month in the backyard of their home before detectives determined his cause of death.

>> Read more trending news

Stephen's family provided WSOC with the following statement on Sunday:

"The family is shocked and mortified at the cause of Stephen's death. All of our family and friends know how much he loved his wife, Lana, and how devoted he was to her. We are all still trying to process this."