Why Would a Fourteen-Year-Old Girl Stab Her Sleeping Sister?

And What Should Happen Next?

Joni E. Johnston, Psy. D.
4 min readJan 18, 2022
copyright free image provided by Manheim Township Police Department

Around 1:00 a.m. on February 22, 2021, a hysterical fourteen-year-old, Claire Miller, dialed 911 in Lancaster, Pennsylvania. “I stabbed my sister. I stabbed my sister. I stabbed my sister,” she repeated over and over. When police arrived at her house, they found her outside, trying to wash the blood off her hands in the snow.

In a bedroom, they found her nineteen-year-old sister, Helen, with multiple stab wounds. A knife was still sticking out of her neck. The parents slept through the whole thing.

Helen had also been asleep when her younger sister attacked her. It would have been hard for her to defend herself even if she’d been awake; she suffered from cerebral palsy and used a wheelchair. She was also nonverbal and would have been unable to call out for help.


Their parents have said the two sisters had a good relationship. Helen was often featured alongside Claire on her social media and appearances at least suggested closeness and affection.

No one has any real idea why Claire wanted her sister dead. Her attorney says Claire didn’t; her violence was due to mental illness, not a murderous heart.

Was Something Wrong with Claire?

Claire has been in jail since her arrest. She is charged with criminal homicide, which equals first-degree murder. Because she committed murder over the age of fourteen in Pennsylvania, she is automatically charged as an adult. Her attorney would have to convince the judge to move her down to juvenile court.

Claire is in a tough situation. Her options are limited, especially since she confessed. In situations like Claire’s, where there is little doubt about who committed a crime, has no previous criminal record, and acts out of character, an insanity plea can be an attractive option. There is some evidence that suggests this may not be just a “Hail, Mary,” the legal equivalent of a last-ditch pass into the endzone when time is running out and your team is about to lose.

Her lawyer, of course, claims that Claire is seriously mentally ill. He has said she exhibited “erratic behavior” in the lead up to her sister’s killing. Shortly after the murder, a witness contacted police and told them she had been on the phone with Claire earlier and Claire had told her she was having “suicidal and homicidal thoughts.” She certainly made no attempt to cover up what she’d done and, according to police reports, was inconsolable when they arrived.

There has also been rampant speculation. Claire was an avid Tiktoker and several of her fans have stated that Claire had been upset with her father around the time of the murder; this has yet to be verified by a credible source. Some of the other scuttlebutt about Claire’s motive isn’t worth repeating.

The Bottom Line

So, what should happen to Claire? Clearly, she is not safe to be released to her parents, even if that were a possibility. Which it is not. She is going to spend some serious time somewhere.

If charged and convicted as an adult, Claire Miller’s sentence will be thirty-five years to life; because she is under eighteen, she will not be eligible for the death penalty or life without parole under Pennsylvania law. If she is tried as an adult and successfully pleads not guilty by reason of insanity, she will be committed to a forensic psychiatric hospital until she is safe to be released. (Trust me; that will not be anytime soon). If she is moved to juvenile court, she could be released at age twenty-one.

Interestingly, if she were in a different state the possible outcomes might be completely different. In California, for example, the Supreme Court recently (2021) upheld a 2018 law that prohibited juveniles under age sixteen from being tried as an adult. This law was a nod to adolescent brain research, which suggests that teens, because of their immature brain development, have lower impulse control, less ability to regulate their emotions, and are more susceptible to peer influence. Because their brains are still developing, the argument goes, they are more likely to be amenable to rehabilitation and intervention.

This law does allow for serious juvenile offenders fifteen and younger to be held until age twenty-five as opposed to the standard twenty-one.

Claire’s day is court is months away, so we’ll have to wait and see what will happen to her. Hopefully, we’ll also get a better sense of what led up to her horrendous decision to kill her only sibling. That’s something of which she’ll never be free.



Joni E. Johnston, Psy. D.

Forensic psychologist/private investigator//author of serial killer book. Passionate about victim’s rights, the psychology of true crime, and criminal justice.