TV3 will air a documentary focusing on the case of missing mum Fiona Sinnott.
Fiona was just 19 when she went missing in Wexford in 1998. She was last seen leaving her local pub Butler's in Broadway on February 8 that year. At the time she had an 11-month-old daughter, Emma.
Despite thousands of hours of investigations by the gardai and her family and even one inspired by a psychic, no sign has ever been found of Fiona since she vanished.
In 2005 her case was upgraded to a murder investigation and six people were arrested and released without charge.
Documentary makers have been working with Fiona's family on the programme, Getting Away with Murder, for the past year and it will air on Virgin Media One (currently TV3) in the autumn.
"We know who killed Fiona," her sister Diane told the Irish Examiner, "For so many years we were afraid to mention names but not anymore."
She added, "I'd have no fear of the suspect. If I came face-to-face with him I'd ask him where my sister is. But he's always hid. The two people with information I believe are fearful of the suspect."
A memorial was held for Fiona in Kilmore in February this year to mark the 20th anniversary of her disappearance.
The memorial began with a mass at Kilmore Church followed by 20 roses being thrown into the sea on the Kilmore Quay beach where Fiona and her sister Diane used to play as children.
Speaking at the memorial, Diane told the Gorey Guardian that she hoped "something will come out of it and somebody will come forward and say something".
"It's really important that we keep Fiona's memory alive and we will continue to do so until we find her," she said.
"Twenty years is a long time with no-one saying anything."
Last year gardai carried out door-to-door enquiries in Wexford and searches were carried out on possible routes Fiona might have travelled to get to her rented house in Ballyhit.
Gardai said they still wanted to hear from about four people who were seen by a passing motorist at Kisha Cross shortly after midnight on the night Fiona disappeared.
"Anyone who can help with this investigation is asked to contact Wexford Garda Station," said Inspector Denis Whelan.