Clues about missing RAF airman Corrie Mckeague are more likely to be in a landfill site than at an incinerator plant, police have said.
The 23-year-old was last seen in Bury St Edmunds, Suffolk, on 24 September.
Suffolk Constabulary ended a 20-week search of the Milton landfill site on 21 July.
Bones found at an incinerator plant are being examined but investigators said it was more likely his remains were in the landfill.
On Tuesday, officers searching the site at Great Blakenham said they had discovered some material that required “further examination” to establish whether there were any links to the missing airman.
A force spokesman said: “The investigation has established that some of the waste collected from Bury St Edmunds is taken to Red Lodge transfer station and from there to Great Blakenham for incineration.
“The strongest likelihood is that Corrie, or anything to connected to him, would be in the waste that was taken to the landfill at Milton, rather than in the incinerated waste, and this was the priority for the investigation.
“However, having not located Corrie thus far in the landfill site then a search of this incinerated material was required.”
Mr Mckeague, from Fife, was last seen entering a bin loading bay in the Suffolk town.
Police said he was known to “sleep in rubbish on a night out” – a claim disputed by Mr Mckeague’s family.