On Wednesday night, Lily Marie Hartwell's mother went to bed in their Port Richey home between 10 and 10:15 p.m. with her two children in their room.
At about 1:45 a.m. on Thursday morning, she woke up smelling smoke and was only able to find her 9-year-old son. After safely getting him out of the house, she re-entered and was still unable to find her daughter.
Fire rescue also had no luck when they looked for her.
It was only hours later that she sent her mother two text messages.
"Mom, I'm so sorry, I don’t know why I did it," she wrote. The next message read, "Did any of u get hurt?"
A search for her took place in the neighborhood, and they found her at a nearby park.
"She had packed her bag that had water, cookies, knives and a couple lighters in it. She fell asleep in one of the park bathrooms," public information officer Eddie Daniels Jr. at the Pasco Sheriff's Office tells PEOPLE.
"Before the fire began she was reading an e-book called Soul Eater and got to a scene where someone gets into a verbal argument and one person was apparently shouting at the other," Daniels says.
She told investigators that this scene triggered an emotion from an argument that she had with her mother about cleaning her room earlier that night.
It was then that she decided to set the house on fire.
Found Fuel in KitchenHartwell changed out of her nightgown so that it wouldn't catch fire and went into the kitchen where she was able to get a bottle of rum and another liquid.
With the liquid mixed together, she poured it on a bed sheet and towel in her garage, set it on fire and left the house.
Investigators were also able to find a diary where she talked about killing.
A line in it reads, "If this keeps up, there will be no safety in this house." Another line says, "Mom, if you ever find this before it happens, I'm sorry."
After being found by investigators, she mentioned that she was intrigued by Slender Man and also talked about the incident that took place in Wisconsin, where two girls who were influenced by the same fictional character were charged with stabbing their classmate 19 times. Their victim returned to school this week.
In a search of Hartwell's computer, investigators found that she frequently visited the website Creepypasta.com, a site that is associated with Slender Man, a fictional character created by Eric Knudsen.
Hartwell has been charged with two counts of attempted murder along with arson.
Authorities are waiting to find out from the Florida State Attorney's office if she will be charged as an adult or a juvenile.