Danny Fitzsimons said he shot his colleague three times in the chest
An ex-soldier accused of murdering two colleagues while working as a security guard in Iraq has sent text messages declaring he acted in self defence.
Danny Fitzsimons, 29, of Rochdale, Greater Manchester, faces the death penalty if he is found guilty.
In text messages sent from his Baghdad prison cell, he said he shot dead the two men last August during a fight in which he feared for his life.
His father Eric and stepmother Liz have asked the UK government to help him.
Mr Fitzsimons was working as a security guard for ArmorGroup when he killed Paul McGuigan, of Peebles, Scotland, and Australian Darren Hoare, both 37, in Baghdad's Green Zone.
He described what he believed happened during the incident in a number of text messages sent to the Guardian newspaper.
'Kill me now'
The family of Mr McGuigan have disputed Mr Fitzsimons' account of what happened.
They said a post-mortem examination showed no defence or fight injuries to the two dead men, who had been shot at close range.
The messages from the murder accused read: "I passed out in a drunken coma. Woke up to find Paul and Darren stood over me. Paul punched me repeatedly.
"Paul grabbed my M4... He cocked the weapon. I pulled the Glock from my vest, chambered a round.
"Paul had already told me he was going to kill me now he had my M4 in his shoulder.
"I shot him three times in the chest."
In a separate text message he admitted losing control during the shooting of his other colleague, Mr Hoare. "I saw blackness then madness," he wrote.
The circumstances surrounding his death were "blotchy at best", Mr Fitzsimons claimed.
The message said: "I know I fought for control of the pistol with Darren and I know I gained control and he was shot at point blank I'm sure."
Mr Fitzsimon's family has called on the UK government to bring him back to face a trial under the UK's justice system.
Mrs Fitzsimons said: "We need help. We need help from the British Government, we need help to try to save Danny's life.
"We need fairness for Danny."
Mr Fitzsimons' defence team and family say he was suffering from post-traumatic stress disorder (PTSD) at the time of the incident.
They put his mental frailty down to experiences he endured while in the British Army.
While in Kosovo he discovered the dismembered body of a child he had befriended - an event that was to lead to his condition, his family said.
Echoing their calls, Clive Stafford Smith, director of legal charity Reprieve, said it was the government's "legal and moral duty" to become involved in the case.
Liz and Eric Fitzsimons have said they want a fair trial for Eric's son
He has called on ministers to make direct representations to the Iraqi government and assist his defence team in building a case.
Mr Stafford Smith said: "Nothing I can say can take away the tragedy of the victims.
"But it is also very important to recognise that Danny Fitzsimons was a huge victim himself."
Mr McGuigan, a former Royal Marines commando from Peeblesshire in the Scottish Borders, had a son and was about to become a father for a second time.
Father-of-three Mr Hoare, from Queensland, served in Iraq as a member of the Royal Australian Air Force before starting work as a private security contractor.
Mr Fitzsimons' Iraqi lawyer Tareq Harb confirmed that the defence team were trying to speak to the families of the two murder victims in a bid to get them to ask the court not to impose the death penalty.
The next hearing in Iraq will take place on April 7.