The continuing fascination with the murder of six-year-old Boulder beauty queen JonBenét Ramsey gets a fresh look this week with the April 28 Netflix premiere of the documentary “Casting JonBenét.” The film, shot entirely in Boulder and directed by Australian filmmaker Kitty Green, turns the camera on the public and the media’s obsession with the still-unsolved 1996 case by compiling 15 months of interviews, auditions, re-enactments and other speculative material gathered in the famously liberal city to Denver’s north. The hybrid documentary/drama made its world premiere at the Sundance Film Festival in January and garnered national attention for its unusual approach to its subject matter.