Private detectives investigating the disappearance of Madeleine McCann are trying to have pedophile Raymond Hewlett undergo a DNA test.

Arriving in Aachen, Germany, on Sunday night, the investigators, hired by Gerry and Kate McCann, are hoping to interview the 64-year-old man to find out what he knows about the disappearance of their daughter, Madeleine.

Mr Hewlett, who is currently undergoing treatment for throat cancer, was living just an hour away from Praia da Luz, and the McCann’s holiday flat, when Madeleine vanished in May 2007.

Although the investigators have no legal authority to interview Mr Hewlett, they are hoping that he will co operate with them in an effort to clear his name.

During the original investigation, DNA samples were taken from the McCann’s holiday apartment, some of which have never been identified. Investigators are hoping that testing Mr Hewlett will shed some new light on the case.

The German authorities are currently investigating the death of his son in a car accident and may insist on obtaining Mr Hewlett’s DNA samples as part of their inquiry.

According to a report in the Daily Mirror, detectives may also be able to use Mr Hewlett’s mobile phone records to establish whether he was in Praia da Luz on the night Madeleine disappeared.

Mr Hewlett, who has lived in Blackpool and Telford, is currently wanted for questioning by West Yorkshire Police in connection with an indecent assault case dating back to 1975.

The McCann’s and their investigation team are hoping that police officers will facilitate a meeting between them and Mr Hewlett once they have finished interviewing him. Sources close to the McCann’s believe that this meeting could take place this week.

Clarence Mitchell, spokesman for Gerry and Kate McCann, said: “Mr Hewlett has denied any involvement in Madeleine’s abduction.

“Our investigators hope he will co-operate by giving them whatever information is needed so they can eliminate him from their investigation.

“It is clear that the man is ill and it is clear he has information that our investigators need.”

Since his connection to the Madeleine McCann investigation, security at the hospital where Mr Hewlett is recovering from throat cancer surgery has been heightened.

Mr Hewlett has been convicted and served time for several sexual offences against young girls, and British police have been trying to locate him for a few years.

Madeleine McCann was approaching her fourth birthday when she was taken from her family’s holiday flat in May 2007. She was sleeping in a bedroom with her two younger brothers while the parents dined at a friend’s apartment nearby. Despite a massive police investigation spanning the whole of Europe, various sightings and worldwide media coverage, Madeleine has still not been found.

The search is now being conducted by two retired policemen, Dave Edgar, a former RUC and Cheshire Police officer, and Arthur Cowley, previously of Merseyside Police, who run Alpha Investigations Group. They have been hired by the Find Madeleine Fund to search for the missing child.