Darkhouse is a 2005 mystery-detective novel written by Irish author Alex Barclay and published by HarperCollins in the United Kingdom, and later in the US, France and many other markets.

The girl's mother Elise Gray is being tailed by Detective Joe Lucchesi, his partner Danny Markey and two FBI agents.

One year passes and Joe Lucchesi has relocated to a small town in Ireland called Mountcannon with his interior designer wife Anna and sixteen-year-old son Shaun.

Joe has taken temporary retirement from the force, Anna is renovating an old lighthouse and Shaun is dating a local girl called Katie Lawson.

She had a secret affair with local drunk John Miller, a man now embittered at his wife having moved to Australia with his children.

Joe does his own investigating, retracing routes that Katie may have taken and asks questions, however, his theories are dismissed by Richie who tells him to stay out of the case.

Duke is very close to his kindly Uncle Bill but has to deal with a lot of hardship in his life in the form of a drug addicted, promiscuous mother and the unwanted attentions of a paedophile.

Donnie also has domestic strife as his father is a negligent alcoholic, while Duke's negative surroundings are moulding him into a deeply disturbed boy with a penchant for violence.

At the age of fifteen the two boys make a chilling blood pact to remain loyal to one another until the end, a precursor to their later dastardly actions.

With Joe now convinced that Duke Rawlins is after him with revenge on his mind, he once again clashes with Richie Bates when he takes Petey Grant in for questioning over the murder.

When he is interrogated by Richie and Frank Deegan he admits that a failed attempt at sexual intercourse had caused Katie to become upset and run away from him.

While researching Duke Rawlins, Joe discovers that Ogden Parnum, a former Police Chief from Stinger's Creek has committed suicide.

Back in Mountbatton, Joe is now convinced that Duke and Donnie are connected to the Crosscut Killer mystery and is liaising with American Detective Victor Nicotero on the theory.

Joe saves a desperate Shaun from a drunken suicide attempt, only to then discover that Anna is missing... Additional flashback sequences to Texas, show how Duke and Donnie embarked upon their sadistic rampage of rape and murder as they callously slayed a succession of innocent young women, proving that they were behind the Crosscut killings.

[2] Powell's Books said of Darkhouse, "In this electrifying thriller—a bestseller in Great Britain and Ireland—Alex Barclay creates a stunning array of contrasts—from the violence of a cop's world to the fragility of an embattled marriage, from the danger of New York's gritty streets to the quiet of a seaside Irish village.

With brilliance and subtlety, Barclay delivers a nerve-wracking tale of a troubled family, facing a brutal danger rushing relentlessly out of the past".