The twisted window by Lois Duncan

Open Road Young Readers, 2012. ISBN 9781453263372.
(Age: 12+) Recommended. Thriller. When Brad Johnson, the new boy at school, takes an interest in her, Tracy Lloyd is unsure of him but promises to help him find his sister. Brad is convinced that his stepfather has kidnapped her and when they finally locate her, Tracy gets a job babysitting. The plan is to turn the child over to Brad, but things do not turn out the way she expects.
This is a thriller that was very hard to put down. Duncan is an expert at building and maintaining suspense and she keeps the tension very high as Tracy gradually gets to know Brad and together they plot how to rescue Mindy. She cleverly draws the reader into the plot, showing the obsession that Brad has with getting his sister back, the loyalty of his friend Jamie and the way that Tracy is vulnerable, not believing that her aunt and uncle love her. This vulnerability makes her wide open to Brad's machinations and she doesn't think through the consequences of her actions.
This taut, well-written thriller is gripping right to the end, with lots of twists and turns that ensured that it was difficult to guess the finale. Although it is a reprint it has not dated and will appeal to anyone who loves a good psychological thriller. It would be ideal to introduce readers to the thriller genre.
Pat Pledger