The case against the parents of missing 4-year-old Madeleine McCann appears to be falling apart as the lead prosecutor admitted that Portuguese authorities have offered no new evidence to warrant continued interviews of Kate and Gerry McCann.

Lead public prosecutor Luis Bilro Verão said in an official statement late Wednesday that the McCanns remain "arguidos," or official suspects, but until new evidence emerges he cannot insist on another interview with them.

"Since the police have not collected any elements of proof after the parents became 'argiudos' on September 7 that justifies any new actions, I have not requested any new interviews,” said Bilro Verão, as reported by The Times of London.

Click here to read The Times of London report.

Two weeks ago, Portuguese police named the McCanns as suspects in the disappearance of their then 3-year-old daughter, Maddy, who vanished from the family's Praia da Luz vacation villa on May 3 while her parents were at dinner.

Reports say that since the McCanns' change in status from victims to suspects in the investigation, authorities have not produced any new details to justify officials' working theory that the couple, both doctors, accidentally killed their eldest child and then tried to hide her body.

The prosecutor's statement follows a review of the evidence by Judge Pedro Daniel dos Anjos Frias, who was asked by Portuguese detectives for permission to re-interview the couple after they refused to answer 40 key questions.

Family spokesman Clarence Mitchell, a former government official who has signed on as the McCanns' public representative, said the couple is encouraged by the latest ruling in the Portuguese court, but they are nonetheless fearful they are being secretly surveilled.

British authorities apparently warned the McCanns that surreptitious surveillance could occur in Portugal, but homeland officials will not say whether such permission was granted in England, according to The Times.

After investigators turned their focus on the family, the McCanns were permitted to return to their home in England with their 2-year-old twins, who were also in the hotel room the night of Maddy's disappearance.

But suspicion about their being bugged has been compounded by the fact that Portuguese law permits eavesdropping on telephones and computers with court approval, even if that request is granted retroactively.

Information gleaned from such activity is also admissible in court. The PolÍcia Judiciária, which sought out the judge's permission to conduct more interviews, has submitted to the court a retroactive application to bug the McCanns, The Times said.

A source close to the couple said the McCanns, even though they have nothing to hide, are very concerned that they and friends of theirs who vacationed with them at the time of the disappearance are all being bugged.

“They are entirely innocent and have nothing whatsoever to hide," a source close to the couple told The Times of London.