Apparently this guy, Eddie Ray Routh had a history of mental troubles.
Routh told a reporter, "It tore my (expletive) heart out when I did it," later adding, "I guess you live and you learn, you know."
After 9/11 happened, there was a surplus of recruits. That dropped off over time and the military needing a lot of recruits they started to drop standards, a recruit didn't need a high school diploma for example, felony convictions were waived, mental issues were waived.
Pretty interesting read. Not sure why he didn't get off due to mental illness.
http://hosted.ap.org/dynamic/stories/U/US_AMERICAN_SNIPER_TRIAL
The verdict capped an emotional trial in which prosecutors painted the 27-year-old as a troubled drug user who knew right from wrong, despite any mental illnesses. Defense attorneys said he suffered from schizophrenia and was suffering a psychotic episode at the time of the shootings. While trial testimony and evidence often included Routh making odd statements and referring to insanity, he also confessed several times, apologized for the crimes and tried to evade police after the crime.
Kyle and Littlefield had taken Routh to the shooting range at Rough Creek Lodge and Resort on Feb. 2, 2013, after Routh's mother asked Kyle to help her troubled son. Family members say Routh suffered from post-traumatic stress disorder from serving in Iraq and in Haiti after the devastating 2010 earthquake.
However, Richardson told Routh that Routh's PTSD claims "have been an insult to every veteran who served with honor."
Routh's mother, Jodi Routh, who was questioned by prosecutors about why she didn't warn Kyle of her son's mental troubles, sat expressionless in the courtroom as the verdict was read.
Routh's defense team said they would appeal the conviction.
Asked by a reporter for The New Yorker magazine in a jailhouse call if he thought about the day he shot the men, Routh replied, "It tore my (expletive) heart out when I did it," later adding, "I guess you live and you learn, you know."
A resort employee discovered the bodies of Kyle and Littlefield about 5 p.m.; each had been shot several times. About 45 minutes later, authorities say Routh pulled up to his sister's home in Kyle's truck and told her he had killed two people.
She called police, who later located Routh sitting in front of his home in the truck. A police video shown by prosecutors showed officers trying to coax him from the truck while he makes comments including: "I don't know if I'm going insane," and, "Is this about hell walking on earth right now?"
"He told us he'd taken a couple of souls and he had more souls to take," Lancaster police Lt. Michael Smith testified.