The sister of Trevor Deely has said some of the online speculation about her brother's disappearance is "outrageous" and needs to be toned down "several notches".
22-year-old Trevor went missing from Dublin city centre on December 7th 2000.
He was last seen on CCTV in the early hours of the morning after attending a work Christmas party.
Over the weekend, gardaí issued a fresh appeal for information on the 19th anniversary of Trevor's disappearance - saying that even the smallest piece of information may assist the investigation.
Speaking on the Pat Kenny Show today, Trevor's sister Michele says the family has kept trying different ways to find Trevor but they keep 'coming up blank'.
She observed: "We've done a huge amount of work... but all that work, in a way, is coming to haunt us - it's really becoming a very difficult item for the family when we think about speculation."
Michele said speculation does happen in the media, but it's "rare" - suggesting that it's the online speculation that needs to "come down several notches".
She observed: "You'd want to read what people write online - it is outrageous.
"At some stage I do think there has [...] something - I don't if it's a ruling or something [like that] - that doesn't allow that occur.
"There's a lot of speculation around Trevor going to Alaska - that was the trip of a lifetime for him... He came home a couple of weeks prior to him going missing - it has nothing to do with anything."
She added: "There's lots of theories - [like] Trevor went to Alaska, got caught up in something and somebody followed him back and did something to him.
"He was a simple guy... he was an entry level IT worker. And [yet] people have him caught up in this banking scam... [or] that he was involved in some crazy scheme, and that's why he was taken. It's crazy."
Michele added that she's been rejected by multiple social media companies when she's brought the concerns to them.
She told Pat: "I battle a lot to get the right facts out there, but it's actually really difficult."
Michele said there have been 'hundreds, if not thousands' of potential witnesses with potential sightings over the years.
She explained: "You never know when you're going to get a story that actually is true... and it could be the worst thing ever.
"But we don't know when that is. As we sit here this morning, there is nothing proven... it feels like forever already.
"Trevor would never give up on us - that's our commitment. As difficult as it is to deal with the speculation... we won't give up. We have to keep fighting through it until we find him."
CCTV footage, which you can see below, shows the last known movements of Trevor Deely.
Footage of the rear entrance of the premises at 3:35am shows an unknown man talking with Trevor at the back gate.
This man has never been identified.
Trevor was last seen on CCTV passing the since-removed Bank of Ireland ATM on Haddington Road at 4.14am.
Around 30 seconds later, a man was captured on CCTV walking in the same direction as Trevor.
Gardaí at Pearse Street Garda station are appealing for any information that could assist the investigation into Trevor's disappearance.
Anyone with information is asked to contact Pearse Street Garda station on 01-666-9000, the Garda Confidential Line at 1800-666-111 or Crimestoppers on 1800-250-025.
