Fifteen-year-old Cassidy Stay lost her entire family -- her mother, father, two younger sisters and two younger brothers -- to a shootout in Texas on July 9. That's when she found strength in the words Albus Dumbledore, the illustrious headmaster of Hogwarts School of Magic in JK Rowling's Harry Potter series. In a speech she made at the memorial just days after the murders, she quoted Dumbledore, "Happiness can be found even in the darkest times if one only remembers to turn on the light."This led to an online campaign to get JK Rowling to contact the teenager. The writer's representative confirmed that the author had written to Cassidy in the voice of Dumbledore, the Telegraph reported.The handwritten note was accompanied by a wand, an acceptance letter to Harry Potter's school Hogwarts, a list of school supplies and a signed book.Its contents were not made public. A spokesman for Rowling told the newspaper: "We can confirm that JK Rowling was in touch with Cassidy Stay, however, the contents of the letter remain private."