(CNN) — A 15-year-old girl and her 11-year-old sister have been arrested in Florida and charged with premeditated murder in the death of their 16-year-old brother, authorities said Tuesday.
Police did not disclose a motive.
The girls themselves tipped off a local police officer to the shooting in their Columbia County home, the sheriff’s office said.
Late Monday, deputies went by to investigate and found the boy’s body on the living room floor.
The children’s parents, Keith and Misty Kornegay, were out of town, and allegedly left the three and an additional 3-year-old daughter unsupervised.
The parents were also arrested and charged with child neglect, the sheriff’s office said. The toddler is being cared for by a child protection agency.
The case is still under investigation, but authorities believe that the older sister took a handgun from their parents’ bedroom and shot her brother. The 11-year-old allegedly assisted her.
While police have identified the girls, CNN is witholding their names since they are minors and have not been charged as adults.
In 2010, the sheriff’s office visited the home on reports of vandalism and a civil matter, CNN affiliate WJAX reported.
Killings are uncommon in Columbia County, which is located between Jacksonville and Tallahassee, Sheriff Mark Hunter told WJAX. There were no homicides there last year.