The family of a young man who vanished without trace as he returned home from a Christmas party almost 20 years ago have warned that unfounded rumours on the internet cause untold hurt and suffering for loved ones.
The warning came as the family of Trevor Deely (22) again appealed for anyone with information about what happened to him in Dublin on December 8, 2000, to contact gardaí.
Trevor's sister, Michele, said a major Garda appeal for information in 2017, on foot of digitally enhanced CCTV security camera footage, had failed to deliver the breakthrough for which they had hoped.
"We are still basically at ground zero," she said.
"We still don't know what happened to Trevor. The gardaí have still not been able to identify the man or men who were standing in the background behind Trevor on the CCTV images."
Michele said what was most hurtful for the family - beyond not knowing what happened to Trevor - was having to deal with the theories and wild speculation by 'armchair experts' on the internet.
"Some of the material in these online chat rooms can really get out of hand," she said.
"It can be very hurtful and distressing for family members who have to read it or who are then asked about it."
Michele said her family remained committed to doing everything they possibly could to assist gardaí in discovering what happened to Trevor.
Her 22-year-old brother, who was from Naas in Co Kildare, had been attending a work Christmas party on December 7 held at the Hilton Hotel on Charlemont Place.
After the party ended, he went with some work colleagues to a popular nightclub, Buck Whaleys, located on Lower Leeson Street.
Trevor left the nightclub and was seen on CCTV footage returning to the Bank of Ireland Asset Management (BIAM) building, where he was employed, to collect an umbrella.
After having a coffee with a workmate, he left around 30 minutes later and was seen on CCTV footage walking past the Bank of Ireland on Haddington Road.
This was at 4.14am on December 8. Trevor was never seen again.
He was reported missing the following Monday when he did not arrive for work as scheduled.
A massive search was launched for Trevor with his father, Michael, placing posters of his son throughout the south inner city area.
Gardaí were supported by search volunteers and examined parks, waste ground, building sites and even local canals and the River Dodder.
But there was no inkling of what happened to the young man.
In 2010, on the 10th anniversary of his disappearance, gardaí launched another appeal for information.
In 2016, gardaí launched a full cold case review and it was decided to re-examine all the CCTV footage.
A specialist UK firm was contracted to digitally enhance some of the images amid indications another individual or individuals may have been in the background behind Trevor.
That work by the UK firm revealed a person or persons in three different portions of the CCTV footage harvested - one segment of which shows a person, a male in dark-coloured clothing, apparently chatting with Trevor.
In another, a person appears to be walking behind Trevor as he walks home just after 4am.
"The gardaí have never been able to tell us that they think the images on CCTV are of the same man," Michele said.
"They explicitly told us that their specialist forensic team could not reach a conclusion on that.
"They do believe the images from the side and back gates of BIAM are of the same man.
"But not the image at 4.14am on Haddington Road. That is important as that man was the only person on that particular CCTV clip not to come forward - there were others on that clip that have been edited out - and hence he is technically the last known person near Trevor who has not been accounted for.
"Keeping Trevor's case in the headlines is very important because we know that is our best hope of helping the gardaí to find out what happened that night," Michele said.
"Unfortunately, there has been nothing new with the case. But we will keep trying. Not knowing what happened has been very difficult for us as a family over the years."
Three years ago, gardaí followed up information with a search of a three-acre property in Chapelizod - at the time describing it as the most significant development in the case for over 15 years.
Unfortunately, the six-week search failed to yield the hoped-for breakthrough.
The six weeks proved "a living nightmare" for the Deely family - and, while the Chapelizod dig was the correct course of action given the information obtained, it has now been forensically determined that Trevor was not there and had never been there.
"It was a complete dead end and there were no follow-on links or leads from it," Michele said.
"But we want people to come forward. That is what we have always been actively campaigning for."
A major renewed appeal is expected next December to mark the 20th anniversary of Trevor's disappearance.
Crimestoppers have offered a €100,000 reward - courtesy of an anonymous donor - for any information which leads to solving the mystery of what happened to Trevor.
The €100,000 reward remains on offer.