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.
More top news
Compared to other EU countries, Britain has taken a small number of refugees fleeing the civil war in Syria - should it be doing more?
Personal details of people who contacted WHSmith has been sent to thousands of magazine subscribers in a mass email following an IT glitch.
A jilted boyfriend has been found guilty of plotting to "horrifically disfigure" his ex-girlfriend by having her doused in acid.