A 12-year-old has been arrested in Christian County, Kentucky after allegedly poisoning her 4-year-old stepbrother.

The incident happened in Oak Grove at a home in the 11200 block of Bell Station Road.

Authorities said the female juvenile’s mother met with deputies when they arrived at the home.

She told them while she was going through Skype messages sent by her daughter, she found some that had been sent to a male living in Texas.

In the messages, the daughter reportedly said she was going to use Mr. Clean to get rid of her young stepbrother.

“Obviously this is not something that’s normal," Captain Chris Miller, of the Christian County Sheriff's Office, said. "It’s quite normal for brothers and sisters to fight, brothers and sisters to disagree. This is kind of above the normal for what we would expect out of that age.”

When the boy became sick, the mother talked to her daughter who admitted to trying to poison the victim.

She told her mother it was because she felt her mother loved him more.

“We’re talking about a 12-year-old here, so we are looking into the mind of a 12-year-old, what bothers her and what makes her tick. This is obviously something that bothered her," Captain Miller said.

Deputies asked to talk to the daughter in the mother’s presence, and when asked why she had poisoned the boy, she said “it was because he was annoying her,” according to police reports.

The juvenile was arrested and charged with murder.

"She’s facing a murder charge because Kentucky does not have an attempted murder charge there. Depending on the outcome of her medical evaluation, that murder charge could be reduced to something else with the same penalty," Captain Miller said.

She was taken to Cumberland Hall for that evaluation.