Kate and Gerry McCann have said they'll take a lie detector test to prove their innocence.
Friends have revealed they want to show they've got nothing to hide over the disappearance of their 4 year old daughter Madeleine.
A friend said: "If they are asked to take a lie detector test by police they would. Kate and Gerry are happy to do anything that will help clear their names."
"They have said all along that they want to co-operate fully with the Portuguese police but, as of today, they have received no such request from the Portuguese authorities."
It comes after prosecutors in Portugal said the pair won't need to return to be re-interviewed, for the time being.
Lie detectors measure physiological responses such as pulse rate, blood pressure levels and skin conductivity when the subject is asked questions. Significant differences in the rates may indicate that the subject is lying.
The McCanns strongly deny any role in the disappearance of Madeleine who vanished from a holiday apartment in the Algarve resort of Praia da Luz on May 3.
The couple, both 39-year-old medical doctors, were with friends at a restaurant just metres away when their daughter disappeared.