Seventeen search teams are part of the operation to find missing five-year-old April Jones.
Earlier today, Insp Gareth Thomas from Dyfed Powys Police discussed the search with our reporter Kevin Ashford.
"It's an incredibly difficult searching environment" he says. "We've got steep mountain sides, dense forestry, and fast-flowing rivers, as well as mineshafts and quarries".
"In this inquiry, I've never seen anything quite like it. Everybody's motivation is incredible. I've been speaking to officers who've not wanted to go on leave, or take rest days, because they want to be involved in the search".