Law enforcement officials released new details about the shooting investigation at Rough Creek Lodge Saturday that claimed the lives of Chris Kyle, 38, and Chad Littlefield, 35.

Erath County Sheriff Tommy Bryant said Kyle, Littlefield and the suspect, Eddie Routh, arrived at the shooting range at Rough Creek about 3:15 p.m. Saturday. He said he believed it was the first time the three had gone target practicing together.

Less than two hours later, a hunting guide found the deceased victims and called 911.

Bryant said both of the men were shot more than once at close range with a semi-automatic handgun, which was recovered Saturday night at Routh's residence in Lancaster. Authorities said they have no motive for what might have prompted the killings.

Routh, who fled the scene in Kyle's truck, was taken into custody after the tires were spiked while he was trying to flee police about 9 p.m. Saturday in Lancaster.

He is being held on a $3 million bond at Erath County Jail, where he is being kept segregated from other inmates.

Bryant did not say Routh was on suicide watch, but did say jail officials were monitoring him closely.

Routh, 25, is an unemployed former Marine who reportedly served in Iraq and Afghanistan. He may have suffered from post traumatic stress disorder and was at the gun range for some type of therapy. Bryant said it appears Routh's mother may have reached out to Kyle for help with her son.

Kyle founded FITCO Cares Foundation, an organization that helps veterans with PTSD.

Kyle is a former Tarleton State University student who wrote the best-selling book, "American Sniper." He was a former Navy SEAL who served four tours of duty in Iraq, where he was given the nickname "The Devil of Ramadi" by insurgents.

Littlefield was a fellow veteran and friend of Kyle's.

His wife Leanne Littlefield is an assistant principal at Walnut Grove Middle School.