First-time writer/director Alexandre Moors’ “Blue Caprice” (⋆⋆⋆½ out of four stars, rated R for disturbing violent content, language and brief drug use) is a true-crime story boasting a confident command of tone and magnetic performances. Isaiah Washington and Tequan Richmond play the man and boy behind the 2002 Washington, D.C., sniper attacks without a false step into mannerism or cliché. John Alle Muhammad (Washington) picks up the castoff 17-year-old Jamaican, Lee Boyd Malvo (Richmond), on a Caribbean holiday, grooming him into a surrogate son and psychological slave. Every shot hints at danger beneath the monotony of their rootless daily life. Opening with a montage of news footage and ending on a prison interview with a young man conditioned to kill, the film exists in a mesmeric twilight zone between realism and cinematic dream state. Spare yet deeply atmospheric, the film is charged with dreadful fatalism. The focus is on the way two unfathomably damaged people create a desperate bond, and their descent into delusion and nihilistic mass murder. Washington, alternately fatherly and sinister, creates the most menacing and believable portrait of a homicidally warped mind since “Henry: Portrait of a Serial Killer.” Moors’ depiction of the duo’s eventual killing spree is more suggestive than grotesque, though several sequences require a strong stomach. Colin Stetson’s score is an eerie balance of haunting orchestral minimalism and goosebump electronica. (St. Anthony Main, 115 SE. Main St., Mpls., $6-$8.50, 612-331-4723.)