After 10 years scratching a modest living as a freelance journalist specialising in contemporary art, Steven Vincent was tiring of the incestuous Manhattan gallery scene. In his mid-forties, he felt he should be doing something else with his life — perhaps something more topical, more relevant. He just wasn’t sure what.

Then, like so many other New Yorkers, he awoke on September 11, 2001 to television images of the World Trade Center on fire. He rushed to the roof of his shabby apartment building on Manhattan’s lower east side.

He watched as a second plane flew into the north tower. He was close enough to see people on fire jumping out of windows. In those searing moments, according to his wife, “he turned into a war correspondent”.

There are many Americans who changed their lives as a result of the horrors of Osama Bin Laden’s attacks, but few who chose so dramatic and ultimately deadly an alternative as Vincent, whose murder in southern Iraq last week has cast an unflattering spotlight on the laissez-faire policies of British troops in the region.

Abandoning the cocktail-fuelled happenings of SoHo and Tribeca, Vincent headed for Baghdad a few months after the American invasion of 2003. He picked up a couple of freelance assignments for US magazines and began to build a reputation as a dogged and fearless observer of the religious rivalries bedevilling the post-war reconstruction process.

He wrote a well-received book, In the Red Zone, about his early experiences in Iraq, and returned last April to research a second book on the southern city of Basra, where British forces have long been struggling to preserve a difficult peace. Last Sunday he enjoyed his finest moment as The New York Times published one of his articles.

It was a scathing critique of British policy in Basra, including incendiary claims that local police were carrying out assassinations using a so-called “death car . . . a white Toyota Mark II that glides through the city streets, carrying off-duty police officers in the pay of extremist religious groups to their next assignment”.

Two days later, Vincent was visiting a money-changer with Nooriya Tuaiz, an unusual 31-year-old Iraqi woman who had become both his Basra interpreter and close friend, when a white car with police markings pulled up beside them.

According to witnesses, at least two men in police uniforms grabbed Vincent and Tuaiz and bundled them into the car.

“One said to bystanders, ‘Don’t interfere, we’re the police, this is our duty’,” his wife, Lisa Ramaci, said last week.

The FBI have told her the car then drove to a warehouse district about five minutes away. For the next five hours witnesses reported hearing screams and shouting from one of the buildings.

“They were calling Noor a whore and a pig for associating with an American,” Ramaci said. “They were screaming at Steven that he was an infidel and deserved to die.”

At 11.30pm last Tuesday, police found two bodies less than three miles from the centre of Basra. Vincent was dead, shot three times in the chest. Tuaiz had also been shot in the chest, but miraculously was still alive. She is recovering in a hospital in Kuwait under military guard.