Police have issued an appeal to trace the body of Emma Faulds after a man was charged with her murder.
Ross Willox, 39, made no plea at Ayr Sheriff Court and is expected to return to court next week.
Ms Faulds, 39, from Kilmarnock, was last seen in Monkton on Sunday 28 April.
Detectives have now confirmed they are conducting inquiries in the South Ayrshire/Dumfries and Galloway border area in an bid to locate her body.
Officers are keen to trace the movements of vehicles on the A714 Girvan to Newton Stewart road on Monday 29 and Tuesday 30 April, particularly Jaguar and Mercedes models.
And police want to speak to anyone who spotted anything odd or out of place within that timeframe in the area of Barrhill, particularly along the A714.
Det Chief Insp Martin Fergus said: “This is a harrowing time for Emma’s family.
“They are in shock and are in the process of dealing with the fact that Emma will not be coming home.
“I am therefore seeking the public’s help in trying to find Emma’s body.”
The officer wants to speak to anyone who may have been travelling along the A714, either north or south between Girvan and Newton Stewart.
He added: “Did you see something a little odd or out of place, perhaps you noticed a car in a lay-by, do you remember anything which struck you as odd at the time?
“I am also keen to speak to anyone who travels this route regularly, northbound or southbound.
“If any motorists have dashcams, please check the footage as it may have captured something which could prove vital to our ongoing inquiries to locate Emma.”