Girl, 15, pleads guilty to sister's murder

MUNDELEIN, Ill. (WLS) -- A 15-year-old girl from Mundelein pleaded guilty to fatally stabbing her 11-year-old sister.

The girl was 14 when she stabbed her half-sister, saying she felt unappreciated by her younger sister.

Under the plea agreement reached with prosecutors, she will be held in juvenile detention for at least five years until her 21st birthday.

The girl will be sentenced on March 3.