Days after the first anniversary of David O'Sullivan's disappearance his mother Carmel has said that she does not believe her son will be found alive but she will continue the search until he is found.
David, who was 25-years-old at the time he went missing, had travelled to California in the US to undertake a popular long-distance hiking trail called the Pacific Crest Trail.
The trail is featured in a book called, Wild: From Lost to Found on the Pacific Crest Trail.
The memoir by Cheryl Strayed, which was later adapted into a film starring Reese Witherspoon, describes a woman's journey of self-discovery as she hikes the trail.
Having read the book a few years ago, David had decided to undertake the 2,500-mile hike.
Speaking to Ryan Tubridy on RTÉ Radio 1 this morning, Carmel said that just before David left for California they sat and watched the film together.
"I suppose I didn't know much about it," said Carmel. "Initially I was saying 'No, no, no, no, you can't do it' but...he was 25 and I couldn't stop him."
Having compeleted a media course as well as a degree in English and Philosophy in University College Cork, David saved money from his job working in a local garage in Midleton to fund his trip.
"What he thought was, when he came back he would probably go back to college and do a Masters or something and he'd never have an opportunity...if he got older and he met somebody and got married and had a mortgage, he'd never be able to take six months off work to do this, he thought.
"So this was his ideal opportunity, it was the right time for him."
In the months leading up to his trip, David trained. He hiked often, hiking the carrauntoohil mountains with weights and even transformed his parent's garage into a "mini-gym".
However, conditions on the Pacific Crest Trail can be snowy and this would not be something that David was used to.
On April 5, 2017, David arrived in a town called Idyllwild around two-and-a-half weeks into his hike.
He stayed in a hotel in the town and left on the morning of April 7. This was the last time that Carmel heard from her son and he has not been seen since.
"We had a few false sightings, some were definitely genuine mistakes and unfortunately we had one up in Washington back in August or September...and we were delighted with the news and he said that he had met him but unfortunately we had it checked out and he was just fooling us really," Carmel said.
Speaking about life since David's disappearance, Carmel told Ryan, "There isn't a moment in my day when I'm not thinking of David and where he could be and where is he and what happened to him and how it happened.
"I need to find him. I really need to know what happened."
Carmel and her husband, Con, have travelled over to the US to take part in searches several times over the past year and are due to go over again to take part in another major search including the outreach in San Diego at the end of this month.
When asked whether Carmel believed she would find her son alive, she responded: "No, I'm afraid I don't.
"He's a year gone, there is no activity in his bank account...he is a very loyal child...he wouldn't do this to us."
She believes that he may have suffered a fall or possibly hypothermia.
You can donate to the search fund to help to find David here.
Listen to Carmel's full interview below.