A military police investigator has criticised a murder probe into alleged SAS executions, claiming senior officers prevented his team from following the evidence.

Delme Williams, who investigated allegations against one SAS unit, told a public inquiry: "It was not a standard investigation where investigators were making decisions based on where the evidence led them." He added that he remained convinced members of British special forces should have been criminally charged.

It is the first time the inquiry, which is examining allegations the SAS committed murders in Afghanistan that were covered up, has heard from those involved in military police investigations into special forces operations. Williams, who served as deputy senior investigative officer for Operation Northmoor which looked at 11 SAS operations, told the inquiry on Monday that the course of the investigation was being "dictated" to his team from above.

He added that he questioned whether the senior Royal Military Police officer in charge, known as the Gold commander, was being "influenced to close the investigation". Williams recalled an occasion during Operation Northmoor when investigators were discussing photographs of one of the 11 SAS operations they were investigating for suspected murder.

The operation involved the fatal shooting of nine people at a home in Nad Ali district, Helmand Province, in February 2011.

The youngest person killed was aged 14.

Williams told the inquiry that, based on his experience as a seasoned crime-scene investigator, he wanted to show the images to a forensics expert. Operation Northmoor investigators suspected those shot had been killed unlawfully, and the photographs showed bullet marks low to the ground, which appeared to undermine the SAS account that those killed had been standing and fired at British forces first, before the SAS returned fire.

Williams told the public inquiry: "A picture paints a thousand words - photos are ideal evidence."

The military police officer said he was "quickly shut down in an abrupt matter" by the Gold commander and when he tried to push back, his senior officer pulled rank and it would have been "insubordinate" to go any further.

He said he believed, to this day, the photographs should have examined by an expert. BBC Panorama investigated the same incident and travelled to Helmand to visit the site of the shooting. An RMP investigator confirmed to the BBC that they had seen photographs from the scene and that the bullet mark patterns had raised alarm among the Operation Northmoor team.

"You can see why we were concerned," the investigator said.

"Bullet marks on the walls so low to the ground appeared to undermine the special forces' version of events."

Panorama's team examined what appeared to be bullet holes from the raid, still visible, which were clustered together on the walls low to the ground. The BBC showed photographs from the scene to forensics and ballistics experts, who said that the clusters suggested multiple rounds had been fired downward from above, and did not appear indicative of a firefight. This supported the version of events put forward by bereaved family members of some who those were killed.

Those relatives have told the BBC those killed were all unarmed civilians who were shot in their beds, and that appears to corroborate the RMP investigators' suspicions.

The BBC reported in 2022 evidence from another Operation Northmoor investigator, who told Panorama: "I believe there was pressure from above to shut down the investigation. It became increasingly clear to me that it didn't matter what evidence we were able to gather, these cases were never going to be allowed to go to court."

At the time, the Ministry of Defence said the incidents had been subjected to "extensive and independent investigation" by the RMP, and no prosecutions had resulted. Operation Northmoor, set up by the RMP's serious crime team, was investigating 45 killings by an SAS squadron in 2011 during a single tour of Afghanistan.

The military police officer told the inquiry the investigation team thought the operational photographs could be important evidence and were looked at "in quite some detail", and the dismissal of this evidence was an example of the way in which the investigation was being run.

Williams told the inquiry there were "outside forces" that seemed to him to be directing the course of the investigation.

"I do recall a general feeling that inquiries were being stopped too soon and that there was no appetite... to pursue all lines of inquiry or for anyone to be referred for prosecution."

During the course of his sworn testimony, Williams was shown a number of internal military documents by the inquiry's lawyers. These records showed it was "confirmed Op NORTHMOOR must end" during an RMP meeting of senior staff in September 2017, while his team were still in the process of gathering evidence.

Williams said he was "not surprised" but that criminal investigations "should never be guided by an end date" imposed on them.

The military police are supposed to be independent from the wider armed forces, but Williams claimed he was shown a briefing note for a meeting between senior military police officers and the deputy chief of the Army at the end of 2017, which set out the intention to close Northmoor.

He remarked he was "surprised to see it written down" but it made sense of the "pressure" he felt the investigation was under.

Williams said he still believed individuals should have been referred for prosecution based on the evidence they had found.

The inquiry also heard that the former head of the British Army, Sir Nick Carter, asked the RMP to cut the staff working on the murder probe to 25, less than a quarter of the team working on Operation Northmoor in 2016.

The police officer in charge at the time, Lt Col John McAllister, believed this would be impossible without having a detrimental effect on the investigation, according to inquiry's lead barrister.

Operation Northmoor was the largest ever murder investigation in the Royal Military Police's history but did not result in any charges.

Alan Pughsley, expert to the public inquiry, has heavily criticised the lack of resources provided to Operation Northmoor and called the decision to close it "premature and inappropriate".

The public inquiry was set up in 2022, following reporting by BBC Panorama that linked one SAS squadron to 54 suspicious deaths on a single six-month tour of Afghanistan.

Panorama found evidence suggesting that members of the SAS had executed handcuffed detainees and children.

The Independent Inquiry relating to Afghanistan is examining allegations that the SAS murdered people during detention operations in Afghanistan between 2010 and 2013, and that senior officials sought to cover up the true circumstances of the killings.

It is also examining whether the Royal Military Police's investigations into such killings were adequate. The RMP evidence is a rare glimpse into the public inquiry's work - much of the evidence is being heard in closed-door hearings.

In January of last year, in the last public evidence sessions, the inquiry heard from its expert witness Alan Pughsley, former chief constable of Kent Police and experienced homicide investigator.

He described how the incredibly complex investigation as fundamentally poorly resourced "from start to finish", hampered by "indecision and apathy" from senior officers, as well as a lack of cooperation from UK Special Forces command.

Pughsley was clear he would not have closed the investigation, particularly at a time when major lines of inquiry were still outstanding.

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