It had to do with the few cells in the LCN DNA (low count number) test itself. They couldn't
even prove the dna sample collected from a vehicle belonged to McCann let alone some other
person, by random chance. One of the scientists involved in the case said 19 markers found in
the LCN test matched 19 of his markers! (using euro codis-23 system). It became a statistical
conundrum.
Later, another better McCann sample was tested against another girl suspected of being
McCann. The tests were a
positive negative.
See: British dna sample under
Disappearance of Madeleine McCann - Wikipedia, the free encyclopedia
and:
http://www.dailymail.co.uk/news/art...and-girl-DNA-sample-prove-missing-Maddie.html