Sentencing took place at Leeds Crown Court in Leeds, England.
The defendant, who appeared in court by remote video-link with her head down and holding a stuffed toy in her hands, had not spoken at any of the previous hearings.
“The level of danger to the public is high. In the circumstances of your continuing silence, the critical question is whether there is any reliable estimate as to how long that danger will continue,” the presiding judge said during sentencing, according to the Daily Mail.
The teenager did not speak to confirm her identity and her refusal to discuss circumstances around the murder has reportedly been problematic for investigators.
“All the experts are hampered by your silence,” the judge said.
The judge told the teenager that the specifics of what happened to Katie Rough continue to be “known only to you,” and that “the utter tragedy and devastation of all this needs no emphasis.”
Her killer was found standing nearby, covered in blood and clutching a knife.
The teenager underwent a mental health assessment prior to sentencing, but psychiatrists were unable to agree on a diagnosis. Suppositions range from a depressive disorder to an emerging personality disorder, according to the BBC.
The judge was told the girl had reported delusional thoughts, depression, self-harm, and suicidal thoughts.
According to prosecutors, the defendant expressed the opinion that people “weren’t human and were robots.”
The teenager’s irrational beliefs may have driven her to try to prove that Katie was not a robot, the court was told at a previous hearing, said the Daily Mail.
According to the BBC, an independent inquiry has been launched by the National Health Service to investigate the treatment the defendant had received before the killing.
“Our story is about a loving home and family that was torn apart on a day when we lost our daughter. ...
“Our story goes on into a future where our home feels very empty, but we will keep going for sake of our other children and our grandson. ...
“We are so grateful for everyone who has helped us in these last months, including the whole community in York, who have been so generous with their kindness, their time and their money. ...
“Katie’s memory will live on in our hearts but also more widely, as a little girl who brought more color to her world.”
“This investigation has been one of the most tragic and challenging I have ever dealt with.There are no positive results from cases such as these.”