The Home Office will pay some of the £2.15m cost of the investigation into the disappearance of Corrie Mckeague, it has been revealed.
The RAF serviceman vanished after a night out in Bury St Edmunds, Suffolk, in September 2016. He is still missing.
Suffolk's police and crime commissioner (PCC) said policing minister Nick Hurd had agreed to award a special grant, expected to be about £800,000.
The Home Office has been approached for a comment.
Suffolk PCC Tim Passmore welcomed the grant.
He said: "Throughout this investigation I have ensured that the constabulary has had the resources it needed but sadly, despite the most extensive search ever carried out in this country, they've been unable to find Corrie."
Mr Passmore said he hoped Mr McKeague's family understood the force "has worked tirelessly" to find him.
He said the grant would be shared between Norfolk and Suffolk police forces as it was a joint investigation.
Mr Mckeague, from Dunfermline, Fife, was last seen about about 03:35 BST in Bury St Edmunds, walking into a bin loading bay.
As part of the inquiry, police trawled a landfill site near Cambridge for Mr Mckeague's remains.
The landfill search ended in December but the police investigation is continuing.
Figures previously obtained by the BBC showed Suffolk Police had spent £1,325,000 on the investigation, plus £826,000 in officers' salaries.
The force said "careful consideration" was given to resourcing all major, long-running investigations.