Nicola Urquhart said she was “trying to keep a sensible head on” after the discovery of human remains in the River Stour in Sudbury, Suffolk on August 27.
Her son Corrie was 23 when he vanished on a night out in Bury St Edmunds, around 16 miles north of Sudbury, on September 24, 2016. He was stationed at RAF Honington.
Suffolk Police said that a post-mortem examination of the bones found in Sudbury was completed on Sunday but “was not able to establish any form of identification or cause of death”.
The force said further tests are now taking place, adding that this will be a “lengthy process”.
Ms Urquhart told the East Anglian Daily Times: “Most times when remains or bodies have been found, the police down in Suffolk have been able to put my mind at rest that it’s not Corrie very quickly.
“After speaking to me, they’ll be able to tell me that they already think they know who the person is or, for whatever reason, they know it’s not Corrie.
“Unfortunately, on this occasion, they’ve not been able to do that.
“So I think the hard thing is that, whether this is Corrie or not, this is somebody’s son or daughter – and it’s whether anybody will ever find out because they might not be able to identify who this person is.”
She added: “It’s just about trying to keep a sensible head on, and not letting your head start making things up and thinking a million thoughts.
“It is really difficult just to wait until you get an answer because there’s as much chance of this not being Corrie as it being Corrie but it’s going to be someone’s son or daughter. It’s just awful.”
The investigation into Mr McKeague’s disappearance was passed to cold case detectives in 2018.
Suffolk Police said the “most likely scenario” is that Mr McKeague went into a bin which was emptied into a lorry and ended up in the waste process.
No trace of him has been found.
NEIGHBOURS SPEAK OUT
Residents have speculated that the black bags were not in the water for long as the river is well maintained and any rubbish is quickly cleared up.
Dog walker Barry Rock, 54, said he saw a Sainsbury’s trolley left beside a parking place on Wednesday evening just 100 yards from where the bags were found.
Police launched a murder inquiry after the bags were recovered form the water on Thursday afternoon next to a submerged shopping trolley.
Mr Rock, a customer services worker at Waitrose, said he believed the shopping trolley he had seen may have been used to carry the human remains.
He said: “My attention was drawn to it because I wondered if it was from Waitrose – but then I saw the orange handle and realised it was Sainsbury’s.
“It was a surprise to see it there because it is about a mile and half from the supermarket. It looked quite new and did not appear to have been in the water.”
The bags were first spotted by a member of the public between Meadow Gates and Croft Bridge in Sudbury. The passer-by alerted a ranger from the Sudbury Common Lands Charity which manages the nearby water meadows.
The ranger fished the bags out and carried them 200 yards to a grass area beside the Roman Catholic church of Our Lady and St John the Evangelist.
The police were alerted at 4.35pm on Thursday when the ranger realised what was in the bags.
Officers set up crime scenes around where the bags were left by the ranger and where they were dumped in the river.
One woman whose home overlooks the river said: “My neighbour was walking with her daughters on the other side of the river at around 11am on Thursday.
“They saw a dumped shopping trolley and there was a man who was acting suspiciously. She said he kept looking at them and the trolley.”
A woman whose home overlooks the area where the bags were left by the ranger said: “One of the officers told me words to the effect that I should not look out of my upstairs window because I might see something unpleasant.
“They later put up a tent on the spot, but they would not tell me what was going on. We have never had anything like this happen before.”
Another resident who asked not to be named said: “I walked past the spot whet the bags were found at about 1pm on Thursday and saw nothing suspicious or odd.
“There were just three girls aged about 13 messing about in a boat. It was an innocent scene, but it is rather chilling to think of it now.
“The river is very well kept and anything that is thrown in is quickly pulled out. That’s why I think the bags could not have been in there for very long.
“This is the weirdest thing that has happened in the 20 years that I have lived here.”