It starts with a little boy walking to his friend’s house to ask him to play, a childhood ritual familiar to everyone.

“Mommy, there’s bodies at Jacob’s with blood on them,” the frantic six-year-old shouts after running back home. “I saw them through the basement window.”

Based on their coverage for the Calgary Herald, journalists Robert Remington and Sherri Zickefoose’s Runaway Devil covers the sensational murder investigation and subsequent trials of a 12-year-old girl identified only as “J.R.” and her 23-year-old boyfriend, Jeremy Steinke. The two were convicted in the stabbing deaths of the girl’s parents and her eight-year-old brother in a suburban Medicine Hat neighbourhood on April 23, 2006.

The book reveals many disturbing facts, including confessions that were ruled inadmissible during the two trials — giving us a fuller portrait of the seemingly mismatched conspirators. “The jury had no idea J.R. had been lying and making excuses,” Zickefoose says in an interview.

“There she was on the stand, a little girl with big wide eyes, playing miss innocent, (saying) ‘I didn’t mean this. I was just kidding.’ We listened to her police interrogation and she lied three times, putting the blame on her lover. We got to see who she really is, I think.”

There are also revelations about Steinke, whose detailed videotaped confession to police officer Chris Sheehan was also kept from the jury because of alleged procedural violations.

“It was a compelling piece of video,” says Remington, “a masterful interview that Sheehan did,” sympathetically persuading the suspect to spill everything. “When Sheehan leaves the room, Steinke is pounding his head on the table, saying, ‘I hope everyone’s fucking happy.’”

The authors have done a masterful job of crafting the true story like a crime novel and combining their long-established skills as senior journalists with a writing flair that proves reality can be just as chilling and compelling as any fictional yarn.

It tells how J.R., a pretty, likable honour student with a middle-class upbringing, abruptly discards her pre-teen innocence and re-creates herself on Internet Goth sites as an older, gun-waving young woman. She calls herself Runaway Devil, among other identities.

Her black attire and online vampire imagery bring her to the attention of Steinke, a trailer-park loner and social outcast who, the book suggests, might be a victim of fetal alcohol syndrome. He supports her outrage over discipline attempts by her anxious mother and father, who see her as spinning out of control. “Their biggest sin,” says Remington, “was they were trying to be parents.”

The lovers soon share text messages and conversations, amplifying J.R.’s desire to kill her parents. She manipulates Steinke into leading the late-night savagery at her house, later claiming her boyfriend misread her anger-induced fantasies as requests. (The evidence strongly implies Steinke killed the parents and J.R. administered the fatal knife blow to her little brother Jacob.) The book’s account of the stabbing deaths, reconstructed from statements and forensic evidence, is chilling.

Zickefoose and Remington skillfully weave in psychiatric analyses and avoid such traps as issuing blanket condemnations of rebellious youth. They quote Goths who insist they are non-violent, but an easy target, especially since the Columbine killings.

Even so, the authors advise parents and teens alike to watch for loved ones whose sudden behavioural changes emit warning signals. Parents, especially, should monitor the social networks and Internet sites their children might have hooked up with.

“If you can’t download music from iTunes or add friends to Facebook, you’ve got work to do,” says Zickefoose. “Even though the parents were familiar with the computer and somewhat adept, this girl ran circles around them, with all the different groups and user names, faking her age.”