North Wales Police has said a cordon around missing vet Catherine Gowing's car will remain in place for some time as a "dynamic" search takes place.
Miss Gowing's Renault Clio was found burned-out in an isolated area of Pinfold Lane, near Mold, close to a disused quarry surrounded by woodland and near to the quarry pool.
Det Supt John Hanson said the area would continue to be cordoned off while a "comprehensive search and extensive examination" takes place.
He also said specialist search teams were examining two other locations in North Wales which have not been identified.
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