STEPHENVILLE, Texas – An Iraq War veteran charged with murdering former Navy SEAL sniper Chris Kyle and a friend turned a gun on the pair while they were at a Texas shooting range, authorities said Sunday.

Eddie Ray Routh of Lancaster was arraigned early Sunday in the deaths of Kyle, who wrote the best-selling book “American Sniper,” and Chad Littlefield, 35. They were killed at a shooting range at Rough Creek Lodge, about 50 miles southwest of Fort Worth.

Travis Cox, director of a nonprofit Kyle helped found, said Sunday that Kyle, 38, and Littlefield had taken Routh to the range to try to help him. Littlefield was Kyle’s neighbor and “workout buddy,” Cox said.

“What I know is Chris and a gentleman — great guy, I knew him well, Chad Littlefield — took a veteran out shooting who was struggling with PTSD to try to assist him, try to help him, try to, you know, give him a helping hand, and he turned the gun on both of them, killing them,” Cox said.

Capt. Jason Upshaw with the Erath County Sheriff’s Office said Routh had not made any comments that might indicate a motive. “I don’t know that we’ll ever know. He’s the only one that knows that,” Upshaw said.

Sheriff Tommy Bryant said Routh was unemployed and “may have been suffering from some type of mental illness from being in the military himself.”

Bryant said he didn’t know whether Routh was on any medication or had been diagnosed with post-traumatic stress disorder.

Routh was being held on one charge of capital murder and two charges of murder.

Upshaw said Routh used a semi-automatic handgun, which authorities later found at his home. Upshaw said ballistics tests weren’t complete Sunday, but authorities believe it was the gun used in the shootings.

The U.S. military confirmed Sunday that Routh was a corporal in the Marines, serving on active duty from 2006 to 2010. He was deployed to Iraq in 2007 and Haiti in 2010. His current duty status is listed as reserve.

Routh is being held on $3 million bond. Bryant said he believed Routh was in the process of seeking a public defender.

Kyle’s best-selling book, “American Sniper: The Autobiography of the Most Lethal Sniper in U.S. Military History,” detailed his 150-plus kills of insurgents from 1999 to 2009. Kyle said in his book that Iraqi insurgents had put a bounty on his head. According to promotional information from book publisher William Morrow, Kyle deployed to Iraq four times.

Bryant said Kyle, Littlefield and Routh went to the shooting range around 3:15 p.m. Saturday. A hunting guide at Rough Creek Lodge came across the bodies of Kyle and Littlefield around 5 p.m. and called 911.

Upshaw said autopsies were still pending and he could not say how many times the men were shot or where on their bodies they were hit.

After the shootings, Routh left the shooting range in Kyle’s pickup truck, Bryant said, first going to his sister’s home in Midlothian, 25 miles southwest of Dallas, where he told her and her husband what he had done. Routh left, Bryant said, and the couple called local police.

Routh arrived at his home in Lancaster, about 17 miles southeast of Dallas, about 8 p.m. Police arrested him after a brief pursuit.

Kyle’s nonprofit, FITCO Cares, provides at-home fitness equipment for emotionally and physically wounded veterans.

“Chris was literally the type of guy, if you were a veteran and needed help, he’d help you,” said Cox, the director of FITCO Cares.

Cox described Littlefield as a gentle, kind-hearted man who often called or emailed him with ideas for events or fundraisers to help veterans.

“It was just two great guys, with Chad and Chris trying to help out a veteran in need and making time out of their day to help him. And to give him a hand. And unfortunately this thing happened,” Cox said.

Bryant expressed a similar understanding of the situation. The sheriff said Routh’s mother “may have reached out to Mr. Kyle to try to help her son.”

“We kind of have an idea that maybe that’s why they were at the range for some type of therapy that Mr. Kyle assists people with. And I don’t know if it’s called shooting therapy, I don’t have any idea,” Bryant said.

Kyle is survived by his wife, Taya, and their two children, Cox said.