Born in April 1974 and raised in rural Texas, Chris Kyle had worked as a cowboy before joining the elite Navy SEALS unit in 1999.

After making it through the notoriously tough selection process, Kyle was deployed to Iraq in 2003 where he made his first long-distance kills even though he had not been trained as sniper.

Spotting his obvious talent, the military sent him to SEAL sniper school, where he was taught how to perform warfare’s loneliest and most controversial job.

In 2004, Kyle was posted to Fallujah, west of Baghdad and a major battleground of Iraqi insurgency, and it was during the battle for that city where he first made his mark. However, it was in 2006 in Ramadi, a city in central Iraq, that Mr Kyle gained his nickname as ‘The Legend’ from his fellow SEALS.

One day, while positioned on a roof, Kyle watched a moped coming down a street. Riding it were two men, one of whom dropped a backpack into a pothole.

Realising that it contained an improvised explosive, Kyle took a shot at the speeding moped from a range of 150 yards. The bullet hit one of the riders, passed through him, and hit the other.

Kyle has been credited with saving hundreds of American lives by making 160 confirmed kills, which is the most in American military history. He claimed to have shot down 255.

In 2009, after four tours of Iraq, Kyle retired and moved to Midlothian, Texas, with his wife, Taya, and two children. He had not only shot more of the enemy than any other American sniper but had also gained himself a chestful of medals, including three Silver Stars for gallantry.

But on February 2, 2013 he and a friend, Chad Littlefield, took 25-year old Eddie Ray Routh to a remote shooting range in Glen Rose, Texas. Before they reached the range Routh, 25, shot both men dead and stole Kyle’s customised pick up truck.

Routh’s family claimed he was suffering from PTSD and had mental issues. His trial on two murder charges begins on February 11.

American Sniper, the movie based on Kyle’s book of the same name, has been a box office hit, but has also divided opinion, with some criticising the film’s jingoistic stance.

The Clint Eastwood directed film, which was produced by and stars Bradley Cooper, has been accused of glorifying murder and serving as war propaganda, most notably by director Michael Moore.