The prime suspect in the high-profile case of Madeleine McCann's disappearance has declined to be interviewed by the Metropolitan Police, the force has said.
The Met reported that an international letter of request was sent to Christian Brückner ahead of his anticipated release for a separate offence, which he later rejected.
German national Brückner, 49, has never faced charges concerning the McCann case and denies any involvement.
Madeleine vanished from a holiday apartment in Praia da Luz, Portugal, in 2007 while her parents dined nearby.
Brückner is currently serving a seven-year prison sentence in Germany for the rape of a 72-year-old woman in Praia da Luz in 2005.
German authorities have stated that he will be released soon.
Despite Brückner's refusal to participate in the investigation, Det Ch Insp Mark Cranwell indicated that the inquiry into Madeleine's disappearance remains ongoing, with the police continuing to explore all viable leads.
The case, which has received significant media attention, has seen German authorities suggesting that evidence like mobile phone data points to Brückner's involvement, although they have not yet found sufficient evidence for prosecution.
Brückner's history includes convictions for sexual offenses, and while police have conducted searches in areas connected to him, they have yet to yield conclusive results. The investigation continues, albeit under different legal interpretations in Portugal and Germany, where authorities consider it a potential murder case while British officials treat it as a missing persons investigation.
Funding for the Metropolitan Police's investigation, Operation Grange, has exceeded £13.2 million since its inception, underscoring the resources dedicated to resolving this long-standing case.