It has been almost 12 years since three-year-old Madeleine McCann vanished while on a family holiday in Portugal.

Despite investigations from Portuguese and British police, countless public appeals and an ongoing Scotland Yard investigation, the case remains unsolved.

Madeleine McCann disappeared when she was three years old on a family holiday in Portugal. Credit:REAL MADRID TV

However, a US expert says fresh analysis of DNA evidence could be the lead investigators need to help crack the case.

“If you have a case that’s important and your goal is to solve it, one would think you’d pursue all possible avenues,” said Mark Perlin, the chief scientist and executive officer of Cybergenetics.