In the summer of 1984, beautiful 15-year-old California high school cheerleader Kirsten Costas is murdered on the street where she lives by a mysterious, knife-wielding assailant – a killer who appears to be another teenage girl! Why would anyone murder one of the most popular girls at school? How did the killer know when and where to target their prey? And who, among all the girls in town, could be the shadowy killer that murdered young Kirsten? It’s a terrifying, heartbreaking high school murder mystery... And now, on a brand-new episode of THIS WEEK IN MURDER, hear the whole shocking story, including details of the bizarre confession that closed the case and shocked the sunny suburb of Orinda. ALSO – An argument in an alley between two women in Iowa leads to a deadly stabbing before the killer flees in a silver Cadillac – but why??? And down in Miami, a young woman is dead and so far, police don’t have any answers. Real-life murder, mayhem and mystery on America’s favorite ...