The Florida teen who shot and killed her brother on Monday had suffered abuse for years, police revealed on Wednesday.

Misty "Ariel" Kornegay, 15, admitted to shooting her 16-year-old brother, Damien, after he allegedly beat her and locked her in a room. Police documents reveal a history of physical and sexual abuse in the household.

Columbia County Sheriff Mark Hunter reported that parents Misty and Keith Kornegay have been charged with neglect causing great bodily harm for repeatedly locking Ariel in a bedroom with only a blanket and a bucket.

Ariel's uncle was charged with molesting her in 2010, and the mother told police she once caught the children having sex with each other.

Keith and Misty left Damien, Ariel, 11-year-old Nicole, and a three-year-old alone in the house while they went out of town on Sunday.

Sheriff Hunter said that Keith was a truck driver, and his unemployed wife would sometimes accompany him on his hauls. Leaving the four children alone was "an accepted practice," Hunter said.

After Damien fell asleep on Monday, Nicole allegedly unlocked the door for Ariel, and kept watch as the teen broke an exterior window to her parents' bedroom and climbed inside. 

Police say Ariel retrieved her parents' 9mm handgun, loaded it, and fired a single shot at her brother, killing him.

Ariel and Nicole then walked nearly four miles to a Dollar General, where Nicole called a friend's mother and told her she ran away. The friend's mother called police, and Ariel confessed the crime to them.

The parents face up to 15 years in prison, and bail was set at $20,000. Keith was ordered to have no contact with the kids, while Misty was allowed supervised visits.

Ariel and Nicole will be held for 30 days in detention facilities while State Attorney Jeff Siegmeister determines whether they will be charged for murder as juveniles or adults. The toddler was taken by a child protection agency.

The case is still under investigation.