The DNA was found in their apartment at the Ocean Club resort. Samples were also found at a nearby apartment used by their friends at the same time, and from a car hired by her parents 25 days after she was reported missing.
Tests carried out by the Forensic Science Service (FSS) laboratory in Birmingham have not proven that the four-year-old was killed, but the results are considered significant.
The FSS is this week expected to complete toxicology tests on samples of Madeleine’s hair to find out if she had been sedated. The tests cannot prove if she died from an overdose. Clarence Mitchell, the McCanns’ spokesman, insisted that the couple could explain any traces of their daughter.