9News understand the push to declare him such was made at Portugal’s request as a 15-year limit on prosecutions was running out.
The man has not been formally identified.
In its announcement, the Faro public prosecutor’s office said the investigation is being run with the help of police and with the cooperation of English and German authorities.
In 2020, German police revealed they were investigating Christian Brueckner, who was already in prison on an unrelated rape charge, as an official suspect.
Madeleine disappeared from her family’s holiday apartment in Praia da Luz, a resort in Portugal, on May 3 in 2007, days before her fourth birthday.
Despite an investigation spanning nearly 15 years, no charges against a suspect have ever been laid.
“It’s huge. This is probably the biggest missing persons case ever worldwide,” forensic criminologist Xanthe Mallet told Today this morning,
“Everybody knows the name Madeleine McCann.
“But even a couple of weeks ago when police in Britain said they were scaling back the investigation, I wasn’t convinced that meant they didn’t have any new leads given what the German police had told us a couple of years ago.
“I was still hopeful. This is a massive, massive day.”