The sister of a missing man has spoken of the "living nightmare" of not knowing where he is, on what would have been his 25th birthday.

Shaun Ritchie, from Fraserburgh in Aberdeenshire, was last seen with friends in woodland area near Strichen after a Halloween night out in 2014.

Four-and-a-half years on, his younger sister has made an emotional plea for those who have any information as to what happened that night to search their conscience and come forward.

Nicole Shand, 22, told STV News: "Since his disappearance it has really affected us. It just feels like every day is a living nightmare.

"It just seems like yesterday. I feel very frustrated as we haven't had the answers and closure that we need.

"I believe someone knows that happened. Please come forward with the information and put our minds at rest and let this heartache stop so we can give him a proper goodbye and get that peace of mind

"If you can take this pain away, come forward. Even with the littlest information - anything may help."

Despite one of the largest searches in the history of Scottish policing, Mr Ritchie has never been found.

CCTV footage captured him at a convenience store in Fraserburgh on October 31 before travelling in a van with a group of friends to a farm in the Greenburn area.

Although a belt, trainers and hooded top belonging to Mr Ritchie were recovered in the days following his disappearance, inquiries soon went cold and there have been no other confirmed sightings.

His family enlisted the help of Glasgow group K9 Search & Recovery and its human remains detection dog in 2015, but the springer spaniel failed to pick up a scent.

They also offered a large £10,000 reward for information on his whereabouts, but have yet to get the answers they are looking for.

Miss Shand said: "It's such a hard thing to go through and to try and accept.

"I go out and put a brave face on, but deep down it is just a horrible thing to live with because we have never had a proper goodbye.

Yet, I remain strong due to having the most amazing support from my partner, my friends and my family.

"It was out of character for Shaun - he always came home.

"I do believe something went on that night. I don't know what happened, but I do believe something did.

"Someone knows what happened that night and I wish they would just come with that information they know to give us the closure and answers."

Miss Shand said she couldn't have asked for a better brother, describing him as "funny, outgoing and truly one of a kind".

She added: "He was just a really friendly person, he was friends with everyone.

"We weren't always the closest brother and sister, but I knew if I needed him he would always be there for me."

On Thursday, Mr Ritchie's family will be marking his birthday by reminiscing on their good times together.

Miss Shand added: "I never want to give up hope for my brother. "I always live in hope that one day he will be found, whether it be five, ten or 15 years from now.

"I will always speak about him and keep him in everyone's thoughts. And I always believe that the truth will come out in the end about what happened on that dreadful night."

Police said they are keeping "an open mind" on the case and will act on any new information provided to them.

Detective chief inspector Lorna Ferguson, who is overseeing the inquiry, said: "Our inquiry into the disappearance of Shaun remains one of the largest ever missing person operations to be carried out by Police Scotland.

"Extensive and detailed searches were conducted with assistance from every specialist air, land and water resource, with more than 200 officers covering more than 22km of ditches, rough terrain and large water areas.

"We were also assisted by the expertise of a forensic soil scientist and geoscientist while intelligence-led information also formed a crucial part of our enquiries with all potential leads pursued by the enquiry team."

The circumstances surrounding Mr Ritchie's disappearance have been reviewed by the Major Investigation Team.

The search activity was also reviewed by Police Scotland specialist search advisors and the National Crime Agency.

DCI Ferguson added: "To date these reviews have all concluded that this remains a missing person inquiry and there is no evidence to suggest that Shaun has been the victim of any crime.

"We will continue to keep an open mind and I can provide every assurance that we will act on any new information provided to us.

"We appreciate how hard it must be for Shaun's family as more years pass - my thoughts are with them at what will be a difficult time."

If you have any information on what happened to Mr Ritchie, call 101 or Crimestoppers anonymously on 0800 555 111.