Police looking for airman Corrie Mckeague have arrested a man on suspicion of attempting to pervert the course of justice.
The 23-year-old, from Dunfermline, Fife, went missing on a night out in Bury St Edmunds, Suffolk, last year.
A 26-year-old man was arrested on Wednesday but has now been bailed.
The man is not the driver of the bin lorry which collected refuse from the area where Mr Mckeague was last seen, Suffolk Police said.
He is not related to the missing gunner, who was based at RAF Honington, the force confirmed.
Police said the man has been bailed to return to police on April 13 while further inquiries are made.
Work is continuing on a landfill site at Milton, near Cambridge, ahead of a police search, which is now likely to start in the next seven days.
Officers have issued CCTV footage of two people who were seen on foot in Brentgovel Street or the "horseshoe" area of the town, around the time of the last sighting of him.
Det Supt Katie Elliott said: "We are continuing to make progress on the investigation and we will be starting the landfill site search as soon as the preparatory work is complete.
"We have been carrying out a lot of inquiries behind the scenes and our work continues to find the truth about what happened to Corrie."
Mr Mckeague had met up with friends on 24 September before heading to a number of bars and Flex nightclub on St Andrew's Street at about 00:30 BST.
He was asked to leave half an hour later and went to Pizza Mamma Mia on St Andrew's Street North. He then took a nap for about two hours in a electrical shop doorway.
At around 03:25, he walked into the "horseshoe" loading bay area.
It has been proven an individual cannot leave the area on foot without being seen on CCTV, but Mr Mckeague was not caught on camera again.
RAF Honington reported Mr Mckeague's disappearance to police on 26 September when he did not turn up to parade at 11:30.
Mr Mckeague's mother, Nicola Urquhart, has previously said she has no faith police would find him and launched a crowdfunding campaign to hire a private investigator.