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
A mother and her boyfriend have been charged over the death of a 19-month-old girl who became trapped inside an oven and was burned.
Babies born at weekends in NHS hospitals are more likely to die in their first week than those delivered on weekdays, new research suggests.
A 16-year-old boy has died after an "altercation" between a group of men in Leicester.