MOSCOW, February 3 (RIA Novosti) – Former Navy SEAL Chris Kyle, who is known as America’s deadliest sniper, has been shot dead at a Texas gun range, local media reported on Sunday.

Kyle, 38, the author of the bestselling memoir "American Sniper," detailing his 150-plus s, was shot in the back during a charity event in Glen Rose, on Saturday, the Texas Department of Public Safety said.

Eyewitnesses said the attacker fired at Kyle and Chad Littlefield, 35, killing both before fleeing in a pickup truck.

The 25-year-old suspect Eddie Ray Routh was arrested in Lancaster, Texas, five hours after a police chase. The motives for the attack remain unclear.

Routh, a former Marine and Iraqi War veteran, was suffering from post-traumatic stress syndrome, media said.

Kyle, an outspoken advocate for war veterans, recorded in his book “American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History” more than 150 sniper kills from 1999 to 2009. The book was released last year.