By Lisa Schwarzbaum
Updated October 31, 2008 at 04:00 AM EDT

Passion drives the hyperactive style of Kurt Kuenne?s very personal nonfiction film: Kuenne?s childhood friend, Dr. Andrew Bagby, was murdered in Pennsylvania in 2001, and the prime suspect, Bagby?s ex-girlfriend and fellow M.D., fled to Canada, where she gave birth to his son, Zachary. Then the story gets worse — deepening a tragedy that Kuenne unspools, with intrusive narrative flourishes, as a surprise horror story. Still, the facts are so awful that Dear Zachary can be forgiven much of its antsiness — as a memorial, as a condolence to Bagby?s parents (who became activists for judicial reform in their late son?s honor), and as a howl of grief. B?