MADONNA is refusing to co-operate with an inquiry into the stadium roof collapse that killed two of her crew in Marseille, France, according to reports. The Queen of Pop had been due to perform at the city's Velodrome stadium last week but the roof of the stage collapsed just days before. A lighting technician, Charles Criscenzo, 53, was killed on the stage, and Charles Prow, 23, from Great Britain, died shortly after at a hospital. At least eight other workers, some part of Madonna's traveling stage crew, were hospitalized. A criminal investigation has been launched into the cause of the accident. The Material Girl singer said last week that she was "devastated" by the accident. "My prayers go out to those who were injured and their families along with my deepest sympathy to all those affected by this heartbreaking news," she said in a statement. All the victims worked for Live Nation, a company which was preparing the show. - SS But the 50-year-old superstar will not be interviewed. A legal source told the UK's Daily Mirror, "She let us know it was impossible. We noted it in the procedure. We regret her refusal."