The DNA mismatch between John Mark Karr and evidence in the JonBenet Ramsey murder was a setback for prosecutors, but they promised to continue searching for the six-year-old beauty queen’s killer.

JonBenet Ramsey murder suspect John Karr arrived today in the Colorado city where the six-year-old was killed to face charges in a case prosecutors said was still in its “very early stages”.

An American expatriate school teacher said publicly today he was with JonBenet Ramsey when she died in what he called “an accident", a stunning admission after a decade without answers in the six-year-old’s murder.