The mother of an Irish man who went missing in the US four years ago says she and her family are still waiting for answers about what happened.
25-year-old David O'Sullivan went missing when he was on the 'trip of a lifetime' to the US back in 2017.
The Cork man had been intending to hike the Pacific Crest Trail - a sprawling 4,250km route between Mexico and Canada.
However, he disappeared just a few weeks into what should have been a five or six-month-long adventure.
On Lunchtime Live, Carmel said the hike was something her son wanted to do after finishing college.
She said: "He saved up for it working in the local garage, and left home on March 20th 2017.”
David had intended to complete the hike and then spend a few weeks in Canada before returning home to Ireland.
He had told his family there would be weeks when he wouldn’t be in touch, as he'd be travelling through remote areas.
However, the family started getting very anxious after more and more time went by without contact from him.
They'd last heard from him on April 7th, when he was resting in a small mountain town called Idyllwild in California.
He left the following morning in good weather conditions, but shortly after a snowstorm descended on the area.
Carmel said: "It’s assumed he got into difficulty because he’d have no experience of the type of snow we’re talking about.
"It’s assumed he slipped and fell to his death.”
The family has been over to California several times, and several searches have been carried out - including a drone search of lower elevations.
However, Carmel said 2020 was an 'absolute disaster' as the search progress completely stalled due to the pandemic.
She explained: "We were intending to go over again in May, and obviously the COVID came… the trail itself was closed down, as the locals didn’t want loads of hikers coming through.
“We couldn’t get over, and there were no searches.
“There was a meeting last night with the drone people in Utah… they’re intending to go down in May. We’re hoping to get a search going.
“We hope to get over again… I don’t know if we’ll make it in May though, with what’s happening with quarantine and everything."
One of the complications of the search is that the family and search teams are dealing with 'vast' areas of land.
Carmel explained: "Idyllwild is a lovely town, but there are around three exits out of it to get back on the PCT.
"We don’t know which one he took, unfortunately… he could have taken any one of the three, and then of course they branch off again.
“When do we get that phone call?"
Carmel told Andrea it was 'heartbreaking' to leave Idyllwild for the first time without any answers about what happened to her son.
She said: “I didn’t want to get in the car or get on the plane.
“The second time we were over there, a call came in as we were heading to the airport to say they’d found something blue at the bottom of a ravine… his bag was blue.
“We didn’t know what to do - did we stay on the chance it was something, or go and fly straight back out the following day? When we got to London there was still no news. It was actually a blue barrel at the bottom of the ravine.
“When do we get that phone call? At the beginning, my phone never left my side."
Carmel said even now, several years later, she still often wakes up during the night and wonders when the family will get an answer about what happened to David.
She said: "We know it’s not going to be good news, but it’s important for us to find out what happened and bring him home.
“He would have been 30 this coming August… he’s still 25 to me - he hasn’t grown old. His friends are settling down - between engagements, houses and their careers. Life for them is great, and please god it all works out for them. But he’ll always be 25 for me - that boy who left home.
"Nobody made him go - he did this of his own accord. But he hasn’t come back, and we’re still searching - and please God we’ll find him.”