Former Navy Seal sniper Chris Kyle shot dead at Texas gun range

A former Navy Seal who went on to write a bestselling book chronicling his life as the US's most prolific marksman has been shot dead at a gun range in Texas.

Police said Sunday that the body of Chris Kyle was found by officers responding to an incident at the Rough Creek Lodge in Glen Rose the previous evening. Chad Littlefield, a 35-year-old friend of the war veteran and author, was also killed at the scene.

In a statement, Sergeant Lonny Haschel said Eddie Ray Routh, 25, of Lancaster, had been charged with two counts of murder in relation to the double shooting. The alleged gunman was found at his home just hours after the shooting, having earlier fled the gun range in a pick-up truck, it is claimed.

Haschel said the link between the men was not immediately clear. Routh was being held Sunday at the Erath County jail on a combined $3m bond, authorities said.

Kyle was a veteran of four tours of Iraq whose shooting during battles in Ramadi and Fallujah earned him the nickname "al Shaitan" or "the Devil" among insurgents who put a bounty on his head.

Kyle drew criticism for drawing attention to his exploits by writing about the 150 insurgents he had killed between 1999 and 2009. The book, American Sniper: The Autobiography of the Most Lethal Sniper in US Military History, became a bestseller.

Early unconfirmed reports suggest that his alleged killer was a former marine.

Routh had sought help from Kyle and his neighbour, Littlefield, according to the director of a veterans group he helped set up.

Witnesses to the shooting told investigators that a gunman opened fire on the men around 3.30pm on Saturday, then fled in a vehicle belonging to one of the victims.

Scott McEwan, who co-wrote American Sniper with Kyle, said he was stunned by his death.

"It just comes as a shock and it's staggering to think that after all Chris has been through, that this is how he meets his end, because there are so many ways he could have been killed" in Iraq, McEwen said.

Trevor Cox, the director of Fitco Cares, a foundation Kyle helped establish for veterans with post-traumatic stress disorder, described Kyle as a humble man who wanted to serve his country and help other and who died "doing what filled his heart with passion – helping soldiers struggling with the fight to overcome PTSD".

Amid unconfirmed reports that Routh was a veteran who Kyle and Littlefield were helping, Cox said that he had not come through Fitco Cares.

Cox, a former US marine corp sniper, said: "The gentleman was not affiliated with our organisation. Any time there is a veteran through our organisation I'm aware of it. So the encounter was not through my organisation."

He said, however, that Kyle and Chad, who were neighbours, also worked with veterans in their own time.

Asked whether it was part of the organisation's program to take veterans to gun ranges, Cos said: "We haven't ever done a shooting event, but in my opinion I don't think there's anything inappropriate in what he was doing something a lot of military people enjoy. This was a senseless act."

"It's important that we continue his legacy and continue to serve veterans fearlessly."

Fitco Cares foundation, an offshoot of Fitco Fitness, provides in-house gyms and fitness equipment to keep soldiers active and also provides counselling and medical networks.

In a statement on the website Fitcocares.org, which is co-ordinating condolences for Kyle, Cox described the former Navy Seal as a hero for his efforts in combat and at home.

"My heart is breaking" said Cox, in the statement. "Our foundation, Fitco Cares, this country and most importantly, his wife Taya and their children, lost a dedicated father and husband, a lifelong patriot and an American hero."

"Chris died doing what he filled his heart with passion – serving soldiers struggling with the fight to overcome PTSD."

In an interview last year with NBC News, Kyle said he didn't want to put the number of kills in the book but the publisher insisted.

"If I could figure out the number of people I saved, that's something I would brag about," he told NBC News' Lester Holt.

After leaving the navy, Kyle founded Craft International, which provides training to military, police, corporate and civilian clients.

At the time of his death, the former Seal was being sued by Jesse Ventura, the former Minnesota governor and ex-professional wrestler, over claims in the book that Kyle punched him in a 2006 bar fight over unpatriotic remarks.

Ventura says the punch never happened and that the claim by Kyle defamed him.

A trial was due for August this year.