The mother of missing airman Corrie McKeague believes CCTV footage shows him leaving the area he was last seen on foot, contrary to the police theory he was taken away in a bin lorry.
Nicola Urquhart wrote in a lengthy Facebook post her son “is not in the landfill, and never was”.
Corrie, of Dunfermline, Fife, was 23 when he vanished on a night out in Bury St Edmunds, Suffolk, on September 24 2016.
His last confirmed sighting was at 3.25am.
“We have been shown CCTV of people in the area ... just after Corrie walked in there,” his mother wrote.
“All are wearing dark clothing. You then see them leaving the area and one is clearly wearing white or very light-coloured trousers.
“I believe this is Corrie. These people leave the area ... immediately after the bin lorry left.”
Ms Urquhart said she “only saw this footage on our last meeting with Suffolk Police”.
She added it is “possible Corrie left on foot and is AWOL” but she has “never believed this is probable, Corrie made no plans, had no reason and has never been seen after the immediate sightings”.
Corrie was stationed at RAF Honington, around 10 miles from Bury St Edmunds.
His mother said she has searched along the A134, a road which runs out of Bury St Edmunds, herself.
“I will continue to do all I can to make sure it is searched and my son is found,” she said.
“I will not give up, neither will Corrie’s brothers or our family.”
Corrie’s father, Martin McKeague, previously shared a statement from Suffolk Police saying a Biffa bin picked up on the day Corrie went missing, in the area where he was last seen, weighed 256lb (116kg) - much heavier than usual.
He said he accepted his son is “gone” but Ms Urquhart questioned data about the bin weight.
Suffolk Police have been approached for comment.