Afterwards, they were taken by car to the spot where Ms Gowing's burnt-out Renault Clio was found last Friday.
The family made no comment.
North Wales Police say they have devoted "extensive" resources to the search, including dog teams and underwater search officers.
Further searches have also taken place at other locations in north Wales and in Cheshire, sources said.
Clive Sharp, 46, of no fixed address, has been charged with murder and appeared before Caernarfon Crown Court on Tuesday, when he was remanded in custody until January 7 when he is due to enter his plea.