The search for missing British toddler Madeleine McCann, who disappeared from a holiday home in Portugal in 2007, has intensified. German investigators say they are homing in on what they believe could be a clue in a yard near the city of Hanover, where they have been digging since Tuesday.

Forensic specialists with cadaver dogs were seen in the lush garden where a jailed German citizen identified as Christian Brueckner, who German police have identified as the prime suspect in McCann’s disappearance, once lived. The 43-year-old suspect is in jail for sex crimes, including the alleged rape of a 72-year-old woman. He is also suspected in other child sexual abuse and missing-persons cases.

“I can confirm that the search is in connection with our Maddie McCann investigation,” Julia Meyer, the spokeswoman for the prosecution told Euronews this week. 

Authorities were using large earth-moving machinery to dig up the entire backyard, according to local news reports. Meyer did not confirm whether they were looking for human remains or further clues in the investigation. 

A tranche of child pornography and little girls’ swimsuits were found at another location where the suspect once lived, officials said.

Police in Portugal have also renewed search efforts based on reports that the German suspect stayed in the area in a beat-up RV at the time McCann went missing. They have unsuccessfully searched around 30 wells for human remains.

McCann was snatched from the bedroom of the vacation rental as her twin siblings slept nearby while her parents dined with friends at a nearby tapas bar in 2007. Police lost valuable time in the investigation concentrating on the parents as primary suspects immediately after the disappearance. The McCanns have not publicly commented on the latest development.