What begins as a poignant tribute to filmmaker Kurt Kuenne's dead best friend snowballs into a gut-wrenching true-crime story in "Dear Zachary: A Letter to a Son About His Father."

What begins as a poignant tribute to filmmaker Kurt Kuenne’s dead best friend snowballs into a gut-wrenching true-crime story in “Dear Zachary: A Letter to a Son About His Father,” a film that, like the twist-filled events it covers, isn’t always what it appears to be. Though presented as a visual scrapbook for the victim’s son Zachary, Kuenne initiated the project before learning Andrew Bagby’s unstable ex-lover was pregnant with their unborn son when the murder was committed. By addressing the memorial to young Zachary, Kuenne lands on a human-interest hook that has made the pic the talk of Slamdance.

Kuenne would probably be the first to admit he’s crafted a shamelessly manipulative version of events, one that works best for audiences who know nothing about the case (which was widely publicized in “Dance With the Devil,” a bestseller written by Andrew’s father, David Bagby). Considering how much more tragedy lies in store, one can hardly fault the helmer for using the elements at his disposal — from a button-pushing piano score to saintly photos and homevideos left behind — to transform his personal tribute into a full-blown polemic. As dozens of oncamera interviews show, those who survived Andrew were angry and hurt by his murder, and the film will leave auds feeling no differently.

When they were kids, Andrew Bagby starred in all Kuenne’s amateur movies, which means the helmer has boxes of footage of his friend. “Dear Zachary” is, above all, a virtuoso feat in editing, and Kuenne uses the material at his disposal to devastating effect. For example, a short film about time travel, in which Bagby can be seen saying, “I’ll go back in time and stop people dying,” takes on a painful new irony in this context.

Rather than letting friends and family share specific memories onscreen, Kuenne blends them together in sweeping, rapidly edited montages. The stories dissolve into one another, leaving audiences with an impressionistic sense of Bagby’s legacy — a succession of smiling faces, it turns out, can say as much as hours of longwinded testimonials.

As for Shirley Turner, the 40-year-old woman (Andrew was 28) who drove 1,600 miles to shoot Andrew after they broke up, Kuenne selects the least flattering footage possible. By crosscutting between court papers and pathological phone messages to Andrew’s parents, Kuenne captures a sense of this deeply disturbed woman.

But there’s more to Turner than meets the eye, and “Dear Zachary” switches gears, attacking the system and the individuals who allowed “a probably premeditated first-degree murderer go free.”

The way Kuenne presents the material, with an aggressive style that lingers less than a second on most shots, it’s impossible not to feel emotionally exhausted.

Dear Zachary: A Letter to a Son About His Father

Production

Produced, directed, written, edited by Kurt Kuenne.

Crew

Camera (color DV), Kuenne; music, Kuenne; sound, Kuenne. Reviewed on DVD, Park City, Utah. (In Slamdance Film Festival), Jan. 22, 2008. Running time: 95 MIN.

With

David Bagby, Kathleen Bagby, Andrew Bagby, Zachary Andrew, Heather Arnold, Shirley Turner, Kurt Kuenne.
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