POLICE believe their disappearances were pre-planned but the cases remain open to investigation until the two women make contact.
The sudden disappearance of Warwick woman Tanya Buckland in August 2014 was initially explained by a letter and photo sent to police not long after the report was filed with authorities.
Similarly, new details in relation to Toowoomba woman Barbara Troughton have reignited calls for information which may lead to the 62-year-old's whereabouts almost 12 months since she was reported missing.
A hand-written note left on a bench inside her Newtown home, and $100 cash taken with her, suggests to police Mrs Troughton had planned her disappearance which remains the subject of an active police investigation.
But in order to close the cases, police need to physically see and speak with the women, Darling Downs Detective Inspector Dave Isherwood said.
"They are both active investigations," Det. Insp. Isherwood said.
"There is evidence to suggest they pre-planned what they were doing."
Det. Insp. Isherwood said Ms Buckland sent a time-stamped photo of herself and a letter to police shortly after she vanished but there had been no further contact or information as to her whereabouts.
Queensland Police Missing Person's Unit head Detective Senior Sergeant Damien Powell told The Courier-Mail Ms Buckland had told her teenage daughter she was going away for a year and was headed to New South Wales, but had failed to make contact with family and friends since.
Det. Snr Sgt Powell confirmed items of Ms Buckland's were found in the home of accused triple murderer Vincent O'Dempsey, but did not know what, if any, involvement she had with the man.
"It's hard to say (why she left), but obviously all our inquiries have drawn a blank," Det. Snr Sgt Powell told the Courier Mail.
"There is no evidence of her (being alive) but she may well have the capabilities to use a different name or work for cash in hand.
"It's just concerning that she hasn't contacted her daughter."
Mrs Troughton was last seen leaving her Newtown home the morning of January 27 last year, getting into a car and driving away.
She is the former owner of a takeaway shop which had fallen into financial difficulties due to a slow holiday season months before she vanished.
Det. Insp. Isherwood said there was nothing to suggest Mrs Troughton had met with foul play, but concerns had grown for her welfare due to the amount of time she had been missing.
The women's disappearances are the only open missing persons cases in the Darling Downs region after the body of Gold Coast man Jamie Hardgraves was found on a Southern Downs property late last year.
Det. Insp. Isherwood urged anyone with information to contact police or Crime Stoppers on 1800 333 000.
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