(CNN) — A former Navy SEAL known for claiming a record number of sniper killings in Iraq was one of two men shot dead at a Texas gun range, allegedly at the hands of a fellow military veteran, officials say.
Chris Kyle, 38, was the author of the best-selling "American Sniper." He and 35-year-old Chad Littlefield, also a veteran, were gunned down Saturday afternoon on the grounds of the expansive Rough Creek Lodge and Resort in Glen Rose, Texas, southwest of Fort Worth, the Texas Department of Public Safety said.
Police later arrested suspect Eddie Ray Routh, 25, and served him with two felony warrants for capital murder.
The three men entered the lodge around 3:15 p.m. (4:15 p.m. ET) Saturday and went to a shooting range located within its 11,000 acres, Sheriff Tommy Bryant of Erath County told reporters Sunday.
A hunting guide tied to the facility found Kyle and Littlefield -- both unconscious -- around 5 p.m. and went to the lodge and called 911, Bryant said. Sheriff's deputies arrived soon after and determined that the two veterans had been shot dead.
It was until about four hours later that the suspect was taken into custody.
Routh's family members could not be reached immediately for comment Sunday. No attorney has made a public statement on his behalf. Bryant said Sunday that he believes the suspect is in the process of seeking a court-appointed attorney.
While Routh's sister said he had admitted shooting Kyle and Littlefield, he didn't explain to her why he did it, Bryant said. Routh isn't believed to have confessed to local authorities about killing the two men. The motive for the killings is unclear.
"I don't know that we'll ever know," said Erath County Sheriff's Capt. Jason Upshaw. "(Routh) is the only one that knows that."
Sheriff: Suspect served four years in Marines
Routh, a former Marine, is believed to have left the service in 2010, a U.S. military official said Sunday. The official had no information on where Routh served or whether he took part in combat. The official spoke on condition of anonymity due to the sensitivity of the situation.
According to Bryant, the Erath County sheriff, he'd served for four years in the Marines. Routh's public records show he previously lived at Camp Lejeune in North Carolina, though his latest address was in Lancaster, Texas.
At the time of shooting, he was unemployed, though Bryant didn't offer many other details. He said that Routh's mother, a longtime schoolteacher, "may have reached out to (Kyle to) try to help her son."
Kyle is best known for his time as a military sniper, having claimed more than 150 such killings during his time in Iraq, which he called a record for any American. He said insurgents placed a bounty on his head and nicknamed him "the devil."
He has also been an outspoken advocate for war veterans, including working with people suffering from issues such as post-traumatic stress disorder tied to their time in the service, Bryant explained. Bryant said he did not know immediately whether Routh suffered from PTSD.
Semiautomatic handgun is suspected 'murder weapon'
The Rough Creek Lodge is a large facility in Texas hill country that attracts couples getting married, business people using its conference center and families looking for a getaway. Hunting and shooting sports are some of the many recreational options available on its grounds.
While there is a record that Kyle, Littlefield and Routh headed to the resort's shooting range, it is believed that there were no witnesses to the shooting. Authorities located what they believe to be the murder weapon -- a semiautomatic handgun -- inside Routh's residence, Upshaw said.
After finding the victims' bodies, and no sign of Routh, authorities issued an alert asking authorities to look for the black Ford pickup truck, with a sticker of a skull on its back windshield, they they believed he drove away in, according to the sheriff.
Around that time, authorities got a call from Routh's sister, who reported that her brother had gone to her own Texas home and admitted to shooting Kyle and Littlefield.
Routh left his sister's home, and police eventually caught up with him -- and the truck -- around 8 p.m. at his home in Lancaster, Texas, about 75 miles away from the shooting scene. He somehow left his residence and got into the truck as authorities were talking to him and was finally stopped around 9 p.m. after his tires were spiked four to six miles down the road.
He did not struggle with officers as they were arresting him, the Erath County sheriff said. On Sunday morning, he was arraigned on murder charges and ordered held on $3 million bond.
'An American hero'
Kyle's friend Jason Kos told CNN's Randi Kaye he was "a man of incredible character. He led by example. He always stopped to take time to talk to whoever was around him. Just incredibly humble, very funny as well."
Kyle helped establish the nonprofit Fitco Cares Foundation to help veterans battling PTSD get access to exercise equipment.
In a statement, the foundation described Kyle as an "American hero" and pledged to carry on his mission.
"What began as a plea for help from Chris looking for in-home fitness equipment for his brothers- and sisters-in-arms" struggling with PTSD turned into an organization that will continue after his death," Fitco Director Travis Cox said in a statement. "Chris died doing what he filled his heart with passion -- serving soldiers struggling with the fight to overcome PTSD. His service, life and premature death will never be in vain. May God watch over his family and all those who considered Chris a true friend."
He leaves behind a wife and two children.
Littlefield, also a veteran working to help people with PTSD, also leaves behind a wife and children, Cox said.
Kyle fought against weapons bans
Kyle served four combat tours in Iraq and received two Silver Stars, among other commendations.
He left the Navy in 2009.
He recently spoke out against weapons bans. In a video interview with guns.com, Kyle accused President Barack Obama of being "against the Second Amendment."
The founding fathers "had the same weapons the military did," he said. "We don't even have that today -- but don't try to take what I've already got."
'Not trying to glorify myself'
In an interview with Time magazine last year, Kyle defended his decision to write a book despite the secretive nature of the SEAL world.
"It's kind of frowned on," he told the magazine. "But I'm not trying to glorify myself. I didn't want to put the number of kills I had in there. I wanted to get it out about the sacrifices military families have to make."
He said that while killing did not come easy at first, he knew it meant saving lives.
"The first time, you're not even sure you can do it," he said in the interview. "But I'm not over there looking at these people as people. I'm not wondering if he has a family. I'm just trying to keep my guys safe. Every time I kill someone, he can't plant an (improvised explosive device). You don't think twice about it."
At one point, Kyle wrote, he shot a woman who was carrying a grenade while with her toddler. But he did not kill a child in Baghdad's Sadr City area who had a rocket-propelled grenade launcher. "According to the rules of engagement at the time, you could kill anyone with an RPG on sight. That day I just couldn't kill the kid. He'll probably grow up and fight us, but I just didn't want to do it.
He said the American public lives "in a dream world. You have no idea what goes on on the other side of the world. The harsh realities that these people are doing to themselves and then to our guys. And there are certain things that need to be done to take care of them."
A lawsuit from former Gov. Jesse Ventura
The book led to a lawsuit. Kyle claimed that he had a bar fight with former Minnesota Gov. Jesse Ventura during a SEAL's wake after Ventura made offensive remarks about SEALs. The book did not include Ventura's name, but Kyle mentioned it in interviews about the book. Ventura insisted that the alleged incident never happened and filed a lawsuit accusing Kyle of fabricating the story. Kyle denied Ventura's allegation. The suit was not resolved.
Before becoming a sniper, Kyle was a Texas rodeo cowboy. He started shooting as a child during hunting trips with his father.
After leaving the military, he founded Craft International, a military training company.
His biography on the company website says that in addition to working with the SEALs, he served with units in the Army and Marines.
His combat experience includes close-quarters battle, desert patrols and training foreign allies, it says.
In the interview with Time (like CNN, a part of Time Warner), Kyle said he did not regret any of his kills. He also said he was "comfortable" with the possibility that that part of his life might be over.
He added, "I'm a better husband and father than I was a killer."