A Pennsylvania teenager has been charged with stabbing her older sister to death early Monday, Lancaster Online reports.

Claire Miller, 14, was “hysterical” when police arrived at the home after the 9th grader herself called 911, according to a probable cause affidavit. She pointed them to a bedroom where they found 19-year-old Helen Miller, who uses a wheelchair, with a stab wound to her neck.

First responders were unable to save her life, and she was pronounced dead on the scene.

Police said they found blood in the snow outside the ranch home in an upscale Manheim Township neighborhood and that Claire appeared to have been trying to wash her hands in the snow. She also had blood on her pants and kept repeating, “I stabbed my sister,” police said.

Officers found Helen Miller with a bloody pillow over her face, covering the large knife embedded in her neck above the chest, the affidavit said. The 19-year-old was lying on her back with her hands near her head. She was pronounced dead at 4:13 a.m.

Manheim Township Police Chief said investigators were “looking for evidence and trying to come up with a timetable and whatever they can find to help them understand what happened,” WGAL reported.

He said investigators believe the parents were home at the time but asleep.

“My heart goes out to them, and I can’t even begin to understand or imagine the pain that they feel at this point,” Rudzinski said.

Claire Miller was arraigned on a murder charge Monday morning and is being held without bond. She is charged as an adult because murder “is not considered a delinquent act in Pennsylvania,” the district attorney’s office said.

For the latest true crime and justice news, subscribe to the ‘Crime Stories with Nancy Grace’ podcast:

[Featured image: Claire Miller/Manheim Township Police Department]