CRIPPLED by guilt, Donna Davidson "hopes" her three-year-old brother was murdered when he vanished more than 40 years ago.
She believes she was so traumatised when Sandy disappeared on April 23 1976 that she "blocked" the pain out and has now been left with no memories of him.
In fact, she only discovered she had a brother five years later aged seven when her mum Margaret sat her down and finally revealed the devastating truth.
But while Margaret can't even bear to hang a photo of her missing son in the house, Donna has fought tirelessly to keep Sandy's case in the public eye.
How they have dealt with their heartbreak isn't the only difference between mum and daughter - while Margaret is convinced Sandy is still alive, Donna believes he was murdered.
Donna, who was two when he vanished, said: "He has been abducted and I hope he has been murdered.
"I can't bear the thought of anything else happening to him like him being taken by paedophiles.
"It sounds horrible but I have had horrible thoughts over what could've happened to him."
Find Every Child Week
EVERY two minutes a child is reported missing in the UK.
This means 80,000 kids vanish without a trace every year.
Children are more likely to be reported missing than adults – one in 200 goes missing each year, while one in 500 adults disappear.
Kids in care are at the highest risk of being reported missing – one in ten compared to one in 200.
The Sun Online has teamed up with as part of their Find Every Child Week campaign.
Each day this week, we will speak to a different family who have been affected by a child’s disappearance.
This marks International Missing Children’s Day on May 25.
If you are away from home or thinking of leaving, or if you have information about a missing person or a missing loved one, call the charity’s free and confidential 24/7 helpline on 116 000 or email [email protected]
On that day in 1976, Sandy and Donna were playing at their grandmother's home in Irvine, Ayrshire, while their parents were at work.
Their pet Afghan hound Kissie ran on to the street and the children chased after her – but moments later Donna returned home alone, saying: "Sandy was away with a bad man."
His disappearance tore the family apart and Donna now has to live with the heartbreaking "guilt" she feels at making it safely back to her gran's house without her big brother.
She said: "I think it should have been me. I often wonder if my family would be happier if it had been me who vanished that day."
Both Donna and Margaret have spoken to The Sun Online as we team up with Missing People as part of their Find Every Child campaign.
Every day, we have featured a different case study ahead of International Missing Children's Day on May 25.
'NOT KNOWING KILLS ME'
For Donna, the hurt following Sandy's disappearance has been both physical and mental.
She has been diagnosed with fibromyalgia - a condition that causes pain all over the body - which she believes was caused by the trauma.
The gaping hole left by Sandy has haunted his family for more than 40 years - his parents splitting because of the strain his disappearance had on their marriage.
Donna said: "His disappearance destroyed the family and I can't stop until I find out what happened to him.
"I would like to think he would've looked for me."
The Big Tweet 2019 - how to help
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Margaret, 65, weeps as she reveals she still has hope her son is alive, saying: "I think somebody took him.
"I've got hope that one day I will get him back.
"It's mother's instinct - I can feel him but the not knowing where he is kills me."
Though the family may be split over what they believe has happened to Sandy, both Donna and Margaret have a shared hatred of how the police have dealt with them over the years.
Margaret is understandably bitter against officers who made her feel "at fault" when he first vanished.
She said: "When Sandy first disappeared, the police questioned us and made us feel guilty for leaving him alone and not being there to look after him.
"It made me feel like it was my fault, that if I'd been there he would still be with us now.
"Since then, all they've done is tell us it's too much money to look into possible new leads. How can you put money on a child?"
Various appeals have been made and numerous bits of information have been passed to police but nothing has come from it.
Eyewitnesses have claimed they saw Sandy leaving in a car with a strange man and a huge search was launched after he vanished with cops knocking on doors and dredging a river.
Over the years, the trail has gone cold in Scotland's longest missing person's case - but Donna continues to pile pressure on officers as they pray for fresh information.
She said: "We were once told Sandy was 'old news', which obviously stung.
"They need to understand we won't give up until we get answers."
Donna says her "whole life" has changed since he vanished but she is determined to make sure his memory lives on.
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She said: "My parents never spoke about Sandy and we weren't even allowed pictures of him up around the house.
"But one morning, his picture was at the side of my bed. It had fallen out of a box or something and I just knew I had to hang it.
"I've told my children and grandchildren about Sandy and talk about him all the time. Sometimes missing people are forgotten about too easily."
Our campaign so far...
- Dad of vanished teen sometimes 'envies parents of murdered kids'
- Time capsule room of missing boy who 'may have been killed by paedo' in 1988
- Sister of girl who vanished on Army base like The Missing reveals her guilt
- Family of UK’s longest missing person beg her to get in touch before they die