Story highlights The 14-year-old called 911, police said 
 
 Officers found her sister upstairs stabbed 40 times 
 
 Neighbors say the sisters seemed close and played together 
 
 The 14-year-old is in a juvenile detention center 
 
 An 11-year-old Illinois girl was stabbed 40 times by her 14-year-old sister, police say, and the reason why has many in the small Chicago-area community of Mundelein reeling in disbelief. 
 
 Police found the 11-year-old girl unconscious and in need of medical attention in an upstairs bedroom of the dwelling Tuesday morning. She later died. 
 
 Because the sister, who called police, initially told officers an intruder was to blame for the attack, authorities briefly placed three schools on lockdown. 
 
 The truth, when it emerged, was even more shocking. 
 
 The 14-year-old, authorities say, repeatedly and fatally stabbed the victim -- her half sister -- with a kitchen knife because the teen thought she was ungrateful. 
 
 JUST WATCHED Police: Teen killed younger sister Replay More Videos ... MUST WATCH Police: Teen killed younger sister 01:23 
 
 "This incident is a heartbreaking tragedy that defies understanding," said Mundelein Mayor Steve Lentz. "I am asking the Chicagoland area, please pray for us. Pray, first of all, for the family that has been devastated by this." 
 
 A group called "Mundelein Moms" is raising money for the girl's funeral and said it raised $6,381 in just one day. There also is an effort to have residents leave their lights on Friday night in remembrance. 
 
 Intruder in the house 
 
 Police received a 911 call about the incident at 8:30 a.m Tuesday. The call came from the 14-year-old girl, said Mundelein Police Chief Eric Guenther. 
 
 The teen told emergency dispatchers that an intruder had barged into the home, attacked her sister and then fled, CNN affiliate WLS reported 
 
 Schools in area were immediately placed on lockdown, Guenther said. 
 
 "The area-wide school lockdown lasted only 15 minutes," he said. 
 
 But the teen's story unraveled quickly. Under police questioning, she admitted to the attack, authorities said. 
 
 Feeling unappreciated 
 
 The teen told police she was mad that her sister didn't appreciate all she did for her, prosecutors said at the suspect's detention hearing Wednesday. WLS was at the hearing. 
 
 The teen said she cooked dinner for her younger sibling and performed other chores. She was also angry that the 11-year-old girl had recently hit her. 
 
 The night before the attack, the teen thought about it for about 10 or 15 minutes, then went downstairs and grabbed a knife, according to prosecutors. 
 
 After the stabbing, she took a shower to wash off the blood, called police and made up the story about the intruder, prosecutors said. 
 
 The 14-year-old was arrested and was charged with murder. 
 
 The case is in juvenile court and a decision could be made in the future to move the case to adult court, the Lake County State Attorney's Office said. 
 
 Playing together 
 
 Those who knew the girls said they lived at the home with their mother. Neighbors said the siblings seemed close. 
 
 The girls were often seen playing together and practicing cheerleading routines, WLS reported. 
 
 "They would always be together," Mary Ann Gryder, a neighbor told the affiliate. 
 
 "The older one would be taking care of the younger one, and vice versa." ||||| Girl, 14, charged with stabbing half-sister, 11, more than 30 times BY JON SEIDEL AND RUTH FULLER Staff Reporters 
 
 Article Extras 
 
 Updated: 
 
 The flush-faced 14-year-old Mundelein girl sat with her palms flat on the table in the Lake County juvenile courtroom, listening carefully. 
 
 She heard a prosecutor lay out the horrific allegations, accusing her of fatally stabbing her 11-year-old half-sister more than 30 times Tuesday simply because the younger girl wasn’t thankful, hit her and made her mad. 
 
 Seated to the teenager’s left in the courtroom was the mother records show the girls shared. The woman appeared stunned, but finally broke down in tears, as she heard the account of her younger daughter’s final moments. 
 
 With every stab of a knife into the 11-year-old’s body, a prosecutor said, the 14-year-old complained the younger girl didn’t show enough gratitude for all she had done. 
 
 That she’d made the girl dinner six times. 
 
 That she’d done her chores. 
 
 That’s why, she allegedly told police, she got up at 7:50 a.m. Tuesday, went downstairs to retrieve a knife and viciously slew her half-sister in the upstairs bedroom of their home in the northern suburb. 
 
 When Wednesday’s hearing ended, a Lake County judge ordered the 14-year-old held in secured detention while she faces charges as a juvenile of first-degree murder. 
 
 The teen was whisked away. Prosecutors said they’ll decide in the coming weeks whether to charge her as an adult. Her family, meanwhile, left the juvenile courthouse without commenting, escorted by security guards. 
 
 The discovery of the younger girl’s dead body led briefly to a lockdown Tuesday of nearby schools after the older girl allegedly told police a Hispanic male broke in, stabbed her half-sister and fled. 
 
 But she later confessed when confronted with hair strands found in her half-sister’s hands — which could be tested for DNA — and revealed an even more troubling narrative that has shaken her far north suburban home. 
 
 “Please pray for us,” Mayor Steve Lentz pleaded at a press conference earlier Wednesday. “This is quite a tragedy.” 
 
 Records show the girls’ mother married the younger sibling’s father in Las Vegas in 2002. She filed for divorce in 2008, records show, two months after accusing him in a petition for an order of protection of pushing her and putting her in a headlock. She also said she hit him back. 
 
 She said it all took place after he threatened to leave the state and take the girls with him, records show. The matter was dismissed three weeks later, according to records. 
 
 Illinois’ child welfare agency said it’s had no prior contact with the family, though. Last spring, the 14-year-old changed her Facebook cover photo to what appears to be a “selfie” taken with her younger sister. 
 
 The two siblings were alone in the house when officers arrived Tuesday morning, answering a 911 call from the 14-year-old claiming an intruder was stabbing her half-sister, police and prosecutors said. 
 
 It’s not clear why the girls were alone. 
 
 The prosecutors said the 14-year-old was crying when she let police in through an interior garage door to look for the intruder. That’s when the prosecutor said they discovered the 11-year-old’s body. 
 
 Lake County Coroner Thomas Rudd said the girl died from “multiple sharp force injuries” which were “consistent with a fillet knife.” 
 
 He said she suffered about 30 stab wounds to the neck, chest and arm. There were three slicing wounds across her face, and another five defense wounds to the palms of her hands, Rudd said. 
 
 She suffered additional bruises, puncture wounds and knife wounds that “nicked” the carotid and right internal jugular vessels, Rudd said. She was also stabbed twice in the left upper lung, he said. 
 
 Investigators interviewed the 14-year-old for hours at the Mundelein Police Department, a prosecutor said. She allegedly told police she heard her half-sister’s screams and saw the man straddling and stabbing her. 
 
 It wasn’t until she was confronted with the strands of hair, the prosecutor said, that she confessed. ||||| Community struggles to come to grips with a 14-year-old girl accused of stabbing her 11-year-old half sister to death. (Published Wednesday, Jan 22, 2014) 
 
 A 14-year-old suburban Chicago girl fatally stabbed her 11-year-old half-sister because she said the younger girl didn't appreciate her, prosecutors said. 
 
 During a Wednesday court hearing, prosecutors said the 14-year-old girl set her alarm early, went downstairs to the kitchen and got a knife. She went back upstairs to her sister's bedroom, prosecutors said, and repeatedly stabbed her sister in bed while telling her how she didn't appreciate the things the older girl had been doing around the house. 
 
 Girl, 14, Charged in Stabbing Death of Half-Sister 
 
 Girl stabbed more than 30 times, police weighing whether to charge teen as an adult. (Published Wednesday, Jan 22, 2014) 
 
 The older girl said she had cooked dinner six times that week, prosecutors said, and the 11-year-old apparently had been hitting her the night before. 
 
 Authorities were called to a home on the 1600 block of Woodhaven Court in Mundelein just before 8:30 a.m. Tuesday on a report of an unconscious juvenile, Mundelein Police Chief Eric Guenther said. 
 
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 The 11-year-old girl was found deceased in a bedroom, Guenther said. The Lake County coroner said she was stabbed 30 times in the neck, chest and arms. 
 
 The 14-year-old girl faces first-degree murder charges. Officials say a decision will be made in a few weeks whether to move the case to adult court. 
 
 Prosecutors said that after the stabbing, the 14-year-old girl called police and told them there was a Hispanic male intruder stabbing her little sister. She again told the story at the crime scene and during police interviews. 
 
 When detectives told her later in the afternoon they had strands of hair that would eventually point to the real suspect, the girl admitted she did it, prosecutors said. She submitted oral and written statements. 
 
 Guenther said the suspect is the one who called 911 to report the emergency and answered the door when police arrived four minutes later. He said whatever transpired happened shortly before the 911 call was placed. Both girls lived in the home with a mother. 
 
 An autopsy performed late Wednesday morning determined sharp-force injuries was the official cause of death. 
 
 "There was evidence of trauma, and while multiple stab wounds were evident, I will defer to the coroner's office," he said. "As to motive, I don't want to comment at this point." 
 
 County coroner Dr. Thomas Rudd said police recovered the knife believed to have been used in the attack and that judging from the injuries it's about 4 inches long. 
 
 The discovery of the girl's body prompted a lockdown of nearby schools. Mundelein High, Mechanics Grove Elementary and Carl Sandburg Middle were placed on alert for about 15 minutes while officers worked to secure the scene, a statement from police said. 
 
 While both girls attended the same school, Guenther declined to identify it. 
 
 "I just want to ask the Chicagoland area to please pray for us," said Mundelein Mayor Steve Lentz. "It's quite a tragedy. It's affected our community quite a bit. We're operating out of a whole new playbook here." 
 
 Prior to releasing their statement, law enforcement officials were mum about what had occurred at the home. A resident reported a stabbing in the area, and another resident said a middle school employee was told there had been a murder in the area. But police initially declined to comment on those reports.
– A shocking story out of a Chicago suburb: Prosecutors say a 14-year-old girl set her alarm for 7:50am Tuesday, woke up, and went downstairs to the kitchen as any normal teenager might do. Except that in this case, police say the girl grabbed a 4-inch long knife, went back upstairs, and stabbed her sleeping 11-year-old half-sister to death—more than 30 times in the neck, chest, and hands, NBC News and the Chicago Sun Times report. Her apparent motive is perhaps even more shocking: With every stab, prosecutors say she told the victim the younger girl was ungrateful for the older girl's housework; the victim had also punched her sister the night before, authorities say. They allege the 14-year-old then showered to wash off the blood before calling 911, telling police a Hispanic male intruder had entered the home the girls shared with their mother—who wasn't home at the time—and did the deed, CNN reports. That led to the lockdown of three nearby schools before the girl's story unraveled. When detectives pointed to strands of hair tying her to the crime, police say she admitted to it, adding that she had contemplated the killing the night before. The girl now faces first-degree murder charges in juvenile court; a decision on whether to move the case to adult court will be made in a few weeks.