Danish girl, 15, stabs mother to death after watching ISIS beheading videos: 'This murder was cold-blooded, ice cold' A 15-year-old girl in Denmark who slaughtered her mother with a kitchen knife after watching sickening ISIS beheading videos online has been convicted of murder. Lisa Borch was sentenced Tuesday, along with her Islamic extremist boyfriend, to nine years in prison following the brutal slay of Tina Römer Holtegaard, the Mirror reported. Prosecutors said the baby-faced blonde teenager and her 29-year-old radical lover Bakhtiar Mohammed Abdulla stabbed Holtegaard at least 20 times in her home in Kvissel, Denmark, last October.