The victim, Dora Betancourt, attended St. John Lutheran School in Libertyville, according to the Chicago Tribune. The Mundelein teen, who is not being named because she is a juvenile, appeared in juvenile court on Wednesday and is charged with first-degree murder, according to the article.
CNN reports the teen felt her younger sibling did not appreciate all that she did, which included preparing meals and other chores, and was also angry that the younger girl recently hit her.
Police say the teen used a kitchen knife and stabbed the 11-year-old girl more than 30 times in the home they shared on Woodhaven Court in Mundelein, according to the Daily Herald.
The teen then called 911 about 8:30 a.m. to report the younger girl had been stabbed. The teen initially told police an intruder was to blame for the stabbing, according to CNN.
The 14-year-old girl, who police said had blood on her arm and wet hair when they arrived, later admitted to the stabbing after police said they told her they found hair in the young girl's hands and that DNA evidence would show who killed the girl, according to ABC7 Chicago. Police said the teen had showered before calling police, according to the article.
The teen is currently charged in juvenile court but officials are considering transferring the case to adult court, according to the Associated Press.
Juvenile Murder Offenders in United States
The Chicago Tribune used FBI data to compile a graphic detailing juvenile murders since 2001 and found boys are much more likely than girls to commit murder. In 2012, 557 boys and 55 girls in the United States committed murder, according to the graphic.