Witnesses in criminal investigations are legally bound to co-operate with the police and do not have the right to silence and face legal actions if they lie.
https://en.wikipedia.org/wiki/Arguido
Indeed it would be a very foolish arguida who accepted everything the police were putting to her as the real deal when their ineptitude was so patently apparent.
SNIP
And so, for the record, this is where we stand on the supposed evidence against Kate and Gerry McCann.
There was never any DNA "proof" that Madeleine's body had been in the couple's hire car - that originated from a misinterpretation by the PJ of inconclusive findings by British forensics experts.
The full report indicates it was the supposed "scent of death" found in the apartment that led directly to the couple's naming as arguidos, but forensics experts have always argued for caution in interpreting sniffer dogs' reactions.
An American court case ruled this kind of evidence inadmissible last year after finding that three supposedly "specialist" dogs were incorrect between 62% and 78% of the time.https://www.theguardian.com/uk/2008/jul/23/madeleinemccann.portugalTwo days later as Eleanor says the McCanns would NEVER have been constituted arguidos for the simple reason the law was changed so that no-one could be made a suspect without supporting evidence.
The fact of the matter is that there never was or had been such evidence.
As far as Justice is concerned it was a shoddy move (no wonder Amaral is the self appointed expert in "scape-goats") and a shameful episode for the Portuguese.