Senior police officers say the Shannon Matthews search is the biggest missing person's inquiry in the area ever and one of the largest searches since the Yorkshire Ripper inquiry 30 years ago.
As the search for Shannon moved into it's fourth week today Chief Inspector Graham Armitage of West Yorkshire Police said: "It's the biggest investigation of its kind now, it's certainly the biggest missing persons inquiry since the Yorkshire Ripper which I also worked on."
Chief Insp Armitage was speaking as teams of specialist dogs were gathered at Crows Nest Park in Dewsbury today.
Officers said the 'victim recovery dogs' were specialists in finding decomposing bodies, there are only 27 such dogs in the country, 16 of them are now working on this investigation with many of them being brought in from Strathclyde, Hampshire, Surrey and Manchester.
However, asked if officers are now looking for a body, Chief Insp Armitage said: "We would like to find Shannon alive."
Woodlands and playing fields in the area around Shannon's home in Dewsbury Moor have now been thoroughly searched. Senior investigator
Chief Supt Andy Brennan said officers were due to work shifts of up to 14 hours as the search continued to show no real clues to Shannon's whereabouts.