The family of murder victim Lisa Dorrian is hoping a new television documentary about her disappearance could help with the search for her body.
Murder in the Badlands, a four-part series produced by the award-winning Fine Point Films, is due to air on BBC1 Northern Ireland next year.
The programmes will focus on the unsolved killings of four women spanning each of the four decades between the 1970s and 2000s.
The victims are Marian Beattie, Inga-Maria Hauser, Arlene Arkinson and Lisa Dorrian.
Shop assistant Lisa (25), who went missing in 2005 and whose 16th anniversary occurs today, will be the final instalment. Her campaigning younger sister Joanne expressed hope that the BBC NI documentary will give added impetus to the search for her body.
She said: "It's been 16 years, but we haven't given up searching for Lisa and we haven't given up hope that someone will be charged."
Filming the documentary begins today, a poignant anniversary date which is emotionally difficult for the Dorrians but one they approach with courage.
"The programme is due to go out next year so this will be the only opportunity to film on Lisa's anniversary," explained Joanne.
"It will be hard for us, but as a family we are determined to do it."
Lisa's tightly-knit family will spend today visiting a memorial bench in her honour in their home town of Bangor and a cherry-blossom tree planted nearby.
"The cherry-blossom is beautiful, it's so girly and a real reminder of Lisa," added Joanne, who is conscious of how the tree's stunning blooms, like the life of her beloved sister, last for only a short period of time.
Detectives probing Lisa's murder believe she was strangled in a mobile home at a Ballyhalbert caravan park, with her body secretly buried afterwards.
After a 16-year investigation they have only one suspect - a male whose role in the killing was covered up because of family relations to senior UVF and Red Hand Commando figures in south-east Antrim.
In a fresh appeal for information about Lisa's disappearance, Detective Superintendent Jason Murphy said: "I recognise that for those who know what happened providing the evidence to the police might be a step too far at this point.
"It is possible, though, to help the Dorrian family out of the daily nightmare that comes with not having Lisa's body.
"Every year the Dorrian family relive this tragic event. However, as time passes they become more and more determined to find Lisa and lay her to rest."
Police sources told Sunday Life that their efforts to locate Lisa would be greatly assisted if Mark Lovett, the last man to see her alive, would speak to them again. The 33-year-old was interviewed immediately after her disappearance in 2005, but has stayed silent since.
In his initial statements Lovett explained how both he and Lisa had been hallucinating as a result of taking drugs in the caravan and heard strange noises outside. He said they fled into the night around 4.45am, with the Bangor woman never seen again.
In the years since, Lovett, now a father-of-two, has been convicted of possessing an offensive weapon and drugs offences.
Also central to the PSNI investigation are telephone calls made to him on the night of the caravan drugs party when Lisa disappeared. DS Murphy says they suggest Lisa had been killed before 4.45am, when Lovett said they fled the caravan.
He told Sunday Life: "I know that Lisa was alive between 10.00pm and 10.30pm. There was a phone call made at 1.15am (to Mark Lovett) and that phone call for me is relevant.
"There is a potential that Lisa was already dead at that stage. My question is, what happens between 10.30pm and 1.15am and what happens between 1.15am and 4.45am?"
Asked if Lisa was murdered between 10.30pm and 1.15am, DS Murphy replied: "There is certainly potential for it."
Following Lisa's murder her killer was protected by relatives with senior positions in the UVF and Red Hand Commando, who purposely shifted the blame onto the rival LVF terror gang.
However, one was recently demoted from his role as 'brigadier' of the South-East Antrim UVF meaning he is no longer able to shield the murderer.
Detectives are hopeful that this, along with pledges from the UVF to abandon criminality, might result in new information coming forward.
To date, police have arrested 10 people in connection with Lisa's death and secret burial, but no one has been charged despite a £10,000 reward. There have been 300 searches and around 4,000 potential witnesses identified.
The Dorrian family are now campaigning for the introduction of a Charlotte's Law in Northern Ireland which would see anyone convicted of murder kept in jail until the location of their victim's body is revealed.
The proposed legislation, which is being considered by Justice Minister Naomi Long, is named after Tyrone woman Charlotte Murray who was murdered and secretly buried by ex-boyfriend Johnny Miller.
If introduced as law it would result in him staying behind bars beyond his minimum 16-year life sentence and until he admitted where he hid her remains.
Anyone with information on Lisa's killing and disappearance should ring the PSNI on the non-emergency 101 number or the Crimestoppers charity on 0800 555 111.