Security company G4S was warned against arming a security guard who killed two of his colleagues in Iraq, a BBC investigation has claimed.
According to the programme BBC Scotland Investigates: Britain's Private War an email signed by a "a concerned member of the public and father" was sent to G4S before Danny Fitzsimons was hired.
It expressed fears over the mental stability of the former paratrooper before he shot dead Scottish security guard Paul McGuigan and Australian Darren Hoare in a whisky-fuelled argument in 2009.
Danny Fitzsimons been previously dismissed from a contract in Iraq after punching a guard
Sent by a former G4S worker, the email read: "I am alarmed that he will shortly be allowed to handle a weapon and be exposed to members of the public.
"I am speaking out because I feel that people should not be put at risk."
Despite the warning, G4S went ahead and employed Fitzsimons for a security contract based in Baghdad.
In a statement the firm said it was aware of the allegations "but following an internal IT investigation it is clear that no such emails were received by any employee before the incident".
Fitzsimons was available for work despite being dismissed from another contract in Iraq because he punched a client, according to the BBC.
Additionally the 31-year-old had been diagnosed with Post Traumatic Stress Disorder, after watching his friend burn to death on a different mission to Iraq. However G4S counter these claims, insisting that though Fitzsimons may have been having flashbacks, they believe no formal diagnosis was made.
Danny was spared the death penalty but sentenced to 20 years in an Iraqi jail
The Mancunian had joined the army at 16 and had been involved in a number of other traumatic missions including a posting to Kosovo, where he discovered the dismembered body of a child whom he had befriended.
He was already facing accusations of firearms offences and assault and had a criminal record when G4S hired him.
After Fitzsimons was sent to Baghdad another anonymous email was sent, according to the BBC. It said:
"Having made you aware of the issues regarding the violent criminal Danny Fitzsimons, it has been noted that you have not taken my advice and still choose to employ him in a position of trust.
"I have told you that he remains a threat and you have done nothing."
36 hours after Fitzsimons arrived in Iraq, he had shot his colleague Paul McGuigan twice in the chest and in the mouth. Australian Darren Hoare was killed by Fitzsimons by a close range shot to the temple.
An Iraqi colleague was also wounded as Fitzsimons attempted to flee the scene.
Paul McGuigan's widow gave birth to her baby prematurely after her partner's death
Fitzsimons was the first Westerner to stand trial in the Iraq following a US-Iraqi security agreement and was jailed for 20 years.
Although he avoided the death sentence, his family raised concerns over whether Fitzsimons would be safe in prison. At the time of the trial, Fitzsimons told the BBC:
"I'll be around thousands of people that I've been at war with since 2005, who've killed scores of American soldiers, British soldiers, military contractors.
"I'll be slung in with those people. You can't sleep with one eye open can you?"
The parents of Paul McGuigan told the programme that they wanted G4S to face charges over their son's death
Corinne Boyd-Russell, from the Borders, said: "Fitzsimons fired the bullets. But the gun was put in his hand by G4S ArmorGroup.
"They put the gun in that man's hand. I want G4S to be charged with corporate manslaughter and be held accountable for what they did."
His father and stepmother said the Ministry of Defence had 'let him down and continue to let down an awful lot of soldiers who come out with PTSD and aren't offered any help.'
The allegations come a week after two bosses resigned over the olympic security shambles, during which the government had to step in with military personnel after G4S failed to provide the required number of guards to staff the event.
A G4S spokesman said:
"This was a tragic case and our thoughts remain with the families of both Paul McGuigan and Darren Hoare, who were valued and highly respected employees of the company, and who continue to be sadly missed by their families, colleagues and friends alike.
We confirmed publicly on 15 September 2009 that, in this particular case, although there was evidence that Mr Fitzsimons falsified and apparently withheld material information during the recruitment process his screening was not completed in line with the company's procedures.
"Our screening processes should have been better implemented in this situation but it is a matter of speculation what, if any, role this may have played in the incident.
"We received two separate medical documents which certified that Mr Fitzsimons was fit to work in Iraq. It subsequently came to light that the most recent of those documents was forged - we believe, falsified by Mr Fitzsimons.
"Mr Fitzsimons was also found to be mentally fit to stand trial by a court of law and before he was found solely responsible for and convicted of the killing of Paul and Darren.
"We have not been shown any formal documentation which proves Mr Fitzsimons had PTSD.
"Our screening processes should have been better implemented in this situation but it is a matter of speculation what, if any, role this may have played in the incident.
"We are aware of the allegation over emails but following an internal IT investigation it is clear that no such emails were received by any employee before the incident. It is not for G4S to comment on the appropriateness of any criminal investigation."
"The company has fully and unconditionally co-operated with enquiries from the police and authorities in both the UK and Iraq at all times."