Camilla Läckberg's The Fjällbacka Murders S00 E01 The Hidden Child

A few months after Erica's parents are killed in a violent car crash, a man arrives on her doorstep claiming to be her brother. Unconvinced, she asks him to leave. But when he's found murdered a few days later, she begins looking through her mother's things and discovers a long hidden secret that someone is very determined to keep secret.