By Daily Mail Reporter and Ryan Gorman PUBLISHED: 21:22 EST, 23 January 2014 | UPDATED: 21:22 EST, 23 January 2014 The 14-year-old girl accused of stabbing her younger sister more than 30 times in their Chicago home set an alarm and arose early to stab the victim while she was in bed asleep, say prosecutors. The girl retrieved a knife from the kitchen in their Mundelein house then entered sleeping 11-year-old Dora Betancourt's bedroom around 7:50am Tuesday, according to the Chicago Sun-Times. She then brutally stabbed and slashed Betancourt with the knife about 30 times, allegedly shouting her complaints against her sister with each thrust, including that the elder had cooked her dinner, and that she had done her chores for her.
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Teen told police she stabbed Dora Betancourt, 11, to death for being ungrateful and mean to her
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The older sister waited for her to fall asleep before killing her, cops said
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She shouted specific reasons for each stab wound while carrying out the frenzied attack, investigators said
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Authorities are mulling whether to charge her as an adult
House of horrors: An 11-year-old girl was found stabbed to death in her bedroom in this @placeholder home, police say her older sister confessed to the murder