A teenage girl who had been reading and writing about the Slender Man allegedly set her home on fire while her mother and brother slept inside, police have said.

Florida police and firefighters were called to the girl’s house after the girl’s mother and her nine-year-old brother escaped a blaze at the family home at 1.45am. The girl was nowhere to be seen and was later located at 5am and taken into custody, the Sun Coast news reports.

The teenager, from Pasco County, allegedly sent a text message to her parents after the fire, which is said to have read: "Mom, I'm so sorry. I don't know why I did it. Did any of [you] get hurt?"

Detectives say she admitted to arguing with her mother before the fire started.

She also reportedly told Florida deputies she had been visiting websites associated with the fictional ‘Slenderman’ internet character.

The Slender Man is often featured in blogs and online forums dedicated to horror stories such as Creepypasta Wiki.

In an unrelated incident in June, a 12-year-old girl was stabbed repeatedly by two classmates who had developed an obsession with the Slender Man meme.

Speaking at a press conference after the incident, Pasco Sheriff Chris Nocco said he wanted parents to be aware “there are things on the internet that are disturbing [and] that are causing kids to lose a sense of reality.”

He said the girl had “written about and talked about” the Slender Man and had also mentioned the stabbing incident in her diary. She had also been reading the online series 'Soul Eater'.