Police Scotland are urging the public to submit any information regarding the Marion Hodge reinvestigation online.
It comes a week after the Unresolved Homicide Investigation Team announced they would be reinvestigating the disappearance of Marion from Lockerbie in July 1984.
The public are being encouraged to submit any information to the Major Incident Public Portal, which is a website that gives the public access to a form so they can send information directly to dedicated teams based at the Scottish Crime Campus.
The senior investigating officer will be appearing on BBC One's Crimewatch Live on 8 March to share the appeal.
Marion is understood to have been dropped off in the Whitesands area of Dumfries around 7.30am on Friday 6 July 1984.
She was reported to be carrying a blue canvas suitcase and brown handbag, wearing a cream high-collared blouse, grey skirt and black sandals.
She was described as 5ft 4in tall, slim build with dark brown collar length hair and she was 34-years-old at the time of her disappearance.
Three days later she was reported missing to Dumfries and Galloway Constabulary.
The mother-of-two lived in Balgray, Lockerbie, and worked in the town’s Clydesdale Bank.
Following her disappearance with no further sightings or contact, Marion was declared legally dead by the Court of Session, Edinburgh, in 1992. Her body has never been found.
Detective Inspector Stephen McGrath, Senior Investigating Officer, said: "The response to our appeal so far has been positive but we are continuing to ask the public to contact us if they have any information that might help.
"Marion’s family and friends deserve closure.
"We’re appealing to anyone who remembers anything unusual leading up to Marion’s disappearance, any sightings in the Whitesands area or any other relevant information that might help our inquiry."
The online form can be found here.