By CHRISTOPHER SHERMAN and JAMIE STENGLE

Associated Press

STEPHENVILLE, Texas

--A 25-year-old Iraq war veteran charged with murdering former Navy SEAL and "American Sniper" author Chris Kyle and his friend turned his semi-automatic handgun onto the pair while they were at a Texas shooting range, authorities said Sunday.

Eddie Ray Routh of Lancaster was arraigned early Sunday on two counts of capital murder in the deaths of Kyle, 38, and Chad Littlefield, 35, at the shooting range about 50 miles southwest of Fort Worth.

Capt. Jason Upshaw with the Erath County Sheriff's Office said Routh used a semi-automatic handgun, which authorities later found at his home.

Routh has not made any comments indicating what his motive may have been, 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."

The military confirmed Sunday that Routh was a corporal in the Marines from June 2006 to January 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 the trio went to the shooting range around 3:15 p.m. Saturday. Someone else came across the bodies of Kyle and Littlefield around 5 p.m. and called 911.

After the shootings, Routh left the shooting range in Kyle's truck, Bryant said, first going to his sister's home, where he told her and her husband what he'd done. The couple called police.

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

Travis Cox, the director of a nonprofit Kyle helped found, told the AP that Kyle and Littlefield had taken Routh to the range to help Routh, who was struggling with PTSD to try to help him.