A person of interest in the Fiona Pender murder investigation left Ireland several years ago, according to a retired detective.
Tuesday is the 26th anniversary of the Offaly woman's disappearance.
The 25-year-old was seven months pregnant when she vanished from Tullamore.
She was last seen at her flat at Church Street at 6am on Friday August 23rd 1996.
Her body has never been found.
Former sergeant-in-charge of the Garda Cold Case Unit is Alan Bailey.
"There are a number of people, who have throughout the years, steadfastly given this person an alibi over the time that Fiona went missing.
"I feel at this stage those people owe it to Fiona, and to the memory of Fiona's child and to the memory of her parents - both of whom have since died - that at this stage they come forward.
"There's nobody going to point the finger at them and say 'You should have done it years ago'".
He believes Fiona knew her killer.
"As a result of my inquiries, I have no doubt that the person responsible for Fiona's disappearance was well-known to her.
"Not alone was Fiona known to the person who caused her to disappear, but the fact that she was pregnant and just six or eight weeks from having her child would also be well-known to this same person.
"There's a person of interest to the inquiry who's living outside the jurisdiction at the moment - he moved away a number of years ago".
