The elite police sniffer dog who found the body of murdered Sion Mills pensioner Attracta Harron has been drafted in to help the hunt for the body of kidnapped toddler Madeleine McCann.

Specially-trained English springer spaniel Eddie and his companion Keela were flown to Praia de Luz complex in the Algarve region of Portugal last week as the search for the missing four-year-old intensified.

The police sniffer dogs, which are trained to locate minute traces of blood, were brought in after the focus of the investigation again turned on the apartment where the McCann family were staying when Madeleine disappeared 97 days ago.

The dogs, which have also been involved in the search for missing Castlederg teenager Arlene Arkinson, were yesterday still in Portugal.

Used across the world for his accuracy, seven-year-old hound Eddie helped police put Trevor Hamilton behind bars in 2006 after the victim recovery dog found 63-year- old Attracta Harron's blood on the 23-year-old murderer's burned-out Hyundai.

Eddie also located Attracta's body in a shallow grave in April 2003, close to Hamilton's home.

The police dog and his handlers returned to Tyrone for a third time at the end of last year to help find the missing Arlene Arkinson who went missing after leaving a disco in Bundoran, Co Donegal, on August 13, 1994.

The identity of the two hounds emerged as reports that sniffer dogs from the UK found specks of blood in the apartment where the four-year-old was last seen.

As Madeleine's parents Gerry and Kate last night clung to the hope that their daughter will be found alive, it is understood forensic tests are being carried out to determine whether the substance is actually blood.

If the tests prove positive, DNA samples could be used to see if there is any match to Madeleine.

Both Eddie and Keela have also been used in various disappearance and murder cases in the US and the Republic.