Although Brueckner has been under investigation for some time in connection with the potential crime, he was only recently branded an "arguido" or official suspect by authorities.
Sources claimed prosecutors asked Brueckner a wide array of hard-hitting questions directly related to her disappearance such as “Where were you the night Madeleine McCann disappeared?” and “If you weren’t by the apartment she disappeared from that night, where were you?” according to the Evening Standard.
Mobile phone records recently revealed that the convicted rapist — who is currently serving time behind bars at Oldenburg Prison — had been at Praia da Luz the night of the little girl's shocking disappearance, and authorities are seemingly determined to make headway on the mysterious case. However, Brueckner refused to answer any of their questions.
"We welcome the news that the Portuguese authorities have declared a German man an 'arguido' in relation to the disappearance of our beloved daughter Madeleine," her parents, Kate and Gerry McCann, spoke out about the news in a statement. "This reflects progress in the investigation, being conducted by the Portuguese, German and British authorities. We are kept informed of developments by the Metropolitan Police."
"It is important to note the 'arguido' has not yet been charged with any specific crime related to Madeleine's disappearance," they continued. "Even though the possibility may be slim, we have not given up hope that Madeleine is still alive and we will be reunited with her."
As OK! previously reported, Madeleine — then only 3-years-old — went missing from her room in 2007 while staying with her parents at Praia da Luz resort in Portugal.
Although her parents were once named suspects in the nearly 15-year-old case, they were never charged and have since been cleared.