Joseph O'Loughlin and Vincent Ruiz novels

Detective Vincent Ruiz, battling amnesia and under investigation by suspicious colleagues within his own department following a brutal attack, turns to psychologist Joe O'Loughlin for help in piecing together the clues to unlock his memory in a case linked to the three-year-old kidnapping and presumed murder of a young girl.

She's standing at the front door. Covered in blood. Is she the victim of a crime? Or the perpetrator?
A teenage girl — Sienna, a troubled friend of his daughter — comes to Joe O'Loughlin's door one night. She is terrorized, incoherent, and covered in blood.
The police find Sienna's father, a celebrated former cop, murdered in the home he shared with Sienna. Tests confirm that it's his blood on Sienna. She says she remembers...

Two missing girls. Two brutal murders. All connected to one farmhouse. Who is to blame?
When pretty and popular teenagers Piper Hadley and Tash McBain disappear one Sunday morning, the investigation captivates a nation but the girls are never found.
Three years later, during the worst blizzard in a century, a husband and wife are brutally killed in the farmhouse where Tash McBain once lived. A suspect is in custody, a troubled young...

When a former student bungles the investigation of a mother-daughter double murder, clinical psychologist Joseph O'Loughlin discovers a link between the case and a series of escalating attacks.