Alan McMenemy, 34, of Milngavie, Glasgow, was one of four security guards kidnapped in Baghdad in 2007 along with the government IT consultant they were protecting.
His body was finally returned to his family in January, more than 1700 days after the former paratrooper, who was the last of his colleagues to be repatriated, went missing. Only computer expert Peter Moore survived captivity.
An inquest into the death of the father-of-two ruled this week that he had been unlawfully killed. Foreign Secretary William Hague yesterday told the House of Commons that he had been brutally murdered.
His widow, Roseleen McMenemy said yesterday: "It is over five-and-a-half years since Alan was kidnapped in Baghdad. As a family we have waited for Alan's return and for this inquest and its verdict of unlawful killing for many years.
"Alan is now home. This has been the most tragic period for us and our grief and sadness continues.
"We have been touched and taken huge strength from all the help and support given to us from people too numerous to mention."
Mrs McMenemy said her thoughts remained with the families of Glasgow-born Jason Cresswell, 39, latterly of Portlethen, near Aberdeen; Alex Maclachlan, 30, from south Wales and Jason Swindlehurst, 38, of Lancashire, who were also kidnapped and murdered by the militants. The four security guards were abducted with Mr Moore, of Lincoln, as they escorted him to the Iraqi finance ministry.
Around 50 to 100 militants in police uniforms ambushed the building, blindfolding the men and bundling them into a vehicle.
The group were moved every few months to different locations.
A film shot by the kidnappers showed Mr McMenemy in a withdrawn state as he spoke of his psychological turmoil over his captivity.
Mr Moore, whose freedom was secured in December 2009 by the release from US custody of militia leader Qais al Khazali, developed a bond with Mr McMenemy as they latterly shared a cell.
The computer expert claimed Mr McMenemy and his security colleagues were killed by the kidnappers in an escape attempt.
An inquest held last year returned a verdict of unlawful killing of the three other hostages, with the coroner rejecting claims they died trying to flee their captors, given their injuries and the fact that two of the bodies were returned bound at the ankles and wrists.
Mr Hague, in a written parliamentary response, said Wiltshire and Swindon Coroner David Ridley had recorded the same verdict on Mr McMenemy at an inquest.
"The coroner concluded that Mr McMenemy had been brutally murdered by his captors. I am sure the House joins me in extending our deepest condolences to the family and friends of Alan McMenemy."
Mr Hague called on the Iraqi government to continue its investigations into the "horrific crimes" and to bring those responsible to justice.