Middle of the Night by Riley Sager

The worst event on Hemlock Circle happened in Ethan Marsh’s backyard when his best friend Billy was abducted during a sleepover. Thirty years later, Ethan returns to his childhood home, plagued by nightmares and noticing strange occurrences, suggesting Billy’s presence. Ethan’s investigation into the past leads him into the surrounding woods and a mysterious institute, revealing that no place is truly safe and the past haunts the present.