LONDON (Reuters) – The parents of Madeleine McCann, the British girl who disappeared in Portugal in 2007 aged just three, said the identification of an imprisoned German child abuser as a murder suspect was a potentially very significant development in the 13-year hunt for their daughter.

The 43-year-old German man, who was not publicly named, lived in the Algarve between 1995 and 2007 and burgled hotels and holiday flats as well as trading drugs, German police said. He is currently in detention over a different matter.

British and German police appealed for information about the man, who has been convicted of child sexual abuse on numerous occasions before, and released photographs of vehicles – a Volkswagen camper van and a Jaguar – which he used at the time.

McCann disappeared from her bedroom on May 3 during a family vacation in the Algarve while her parents were dining with friends nearby in the resort of Praia da Luz.

German police said the suspect, who lived near Praia da Luz, has been sentenced on numerous occasions to prison terms for sexual abuse of children in the past.

They said they were treating the case as a suspected murder and had determined the method used to kill McCann, although it was not clear how they had done so. No body has ever been found.

The disappearance of Madeleine sparked a hunt, with missing posters of the little girl’s face papered across the world and celebrity appeals for information that could help track her down and bring her abductors to justice.

“All we have ever wanted is to find her, uncover the truth and bring those responsible to justice,” her parents, Kate and Gerry, said in a statement.

“We will never give up hope of finding Madeleine alive but whatever the outcome may be, we need to know as we need to find peace.”

A family spokesman, Clarence Mitchell, said her parents felt the police announcement was “potentially very significant.”

Detective Chief Inspector Mark Cranwell, who leads Britain’s investigation, said: “We have been working with colleagues in Germany and Portugal and this man is a suspect in Madeleine’s disappearance.”

The case remained a missing person inquiry, Cranwell said.

Police said they wanted to speak to a thus-far unidentified second person who spoke with the German suspect from a Portuguese phone number on May 3, 2007 at the time of McCann’s disappearance.