The suspect in the Madeleine McCann case has been moved to solitary confinement to protect him from fellow prisoners.
Christian Brueckner, 43, is also receiving counselling on how to deal with intense media scrutiny.
The former car mechanic and convicted paedophile is in a high security prison in the northern German city of Kiel on drugs charges. He was identified as a suspect in the Madeleine case last week, more than 13 years after the little girl went missing on holiday in the Algarve.
And yesterday the German prosecutor running the investigation revealed his team has not shared all their evidence with their Portuguese counterparts.
Hans Christian Wolters said he believed the Portuguese still harbour suspicions about Madeleine's parents, Kate and Gerry. The couple, from Rothley in Leicestershire, were infamously named as "arguidos", or suspects, after their 3-year-old daughter's disappearance.
Despite being cleared by the Portuguese attorney general they have been subject to slanderous accusations.
Wolters said: "Working together with authorities in south European countries is generally more time-consuming. We do stay in contact with the colleagues in Portugal, but everything is more cumbersome."
Asked if evidence had been shared with the Portuguese recently, Wolters replied: "Not everything. The Portuguese officials still think that Maddie's parents are responsible for her disappearance.
"From our perspective, the suspect is in jail in Germany right now. We think that the parents don't have anything to do with it. We are convinced our 43-year-old suspect is the murderer of Maddie McCann.
"Yesterday, the justice minister in the northern state of Schleswig-Holstein said Brueckner had been 'isolated from the other prisoners in a section where he could be monitored more closely'."
Wolters said he believed Madeleine was killed soon after she abducted from her family's holiday flat in Praia da Luz.
He added: "We have evidence, strong evidence but we cannot make it public and it points to Maddie being dead. We have strong evidence that she is dead and she wasn't held for a long period of time with our suspect or anyone else."
Brueckner's ex-girlfriend is being looked after by social workers. Nakscije Miftari, 25, was in a relationship with him when she was just 17 and he was 37. Friends said she was terrified when she discovered her ex had been linked to the Madeleine case.
Yesterday her sister Azra said she had been interviewed by German detectives, who had been trying to find her.
"Brueckner hit my sister. It was horrible for her," she said. "I know what he did to her. They have told Nakscije not to speak about Brueckner."