Washington The shooting death of a former Navy SEAL , who spent his post-military career advocating for veterans suffering from post traumatic stress disorder , highlights long-standing differences over gun rights and mental health . Chris Kyle , the author of the best-selling `` American Sniper , '' and Chad Littlefield , 35 , Kyle 's friend , were gunned down on Saturday while shooting for fun at a Texas gun range , law enforcement officials said . Eddie Ray Routh , 25 , a former Marine who told police last year he was suffering from post traumatic stress , was held on a capital murder warrant , authorities said . Shay Isham , a lawyer appointed to represent him , said his client spent roughly the past two years in and out in Veteran Affairs medical facilities for treatment of mental issues . Authorities said Kyle , 38 , often took veterans with post traumatic stress to the gun range as a way of bonding with and mentoring them . Erath County Sheriff Tommy Bryant said Routh served in the Marines for four years , but it was unclear how much of that time , if any , was spent in combat zones . Kyle and LIttlefield , friends and associates , arrived with Routh at the sprawling range southwest of Fort Worth together , police said . The suspect was `` a troubled veteran whom they were trying to help , '' said Craft International , a company founded by Kyle after retiring from the Navy in 2009 . Ex-Navy sniper , another military vet killed at Texas gun range . `` Chris Kyle 's death seems to confirm that 'he who lives by the sword dies by the sword . ' Treating PTSD at a gun range does n't make sense , '' former Texas Republican Rep. Ron Paul tweeted on Monday . But what seems like common sense to some is viewed by others as another assault on the Second Amendment . Those types of concerns are what prompted a heated debate last December as lawmakers worked to approve a defense policy bill . Republican Sen. Tom Coburn pushed and then backed away from an amendment to block the Department of Veteran Affairs from automatically entering the names of veterans deemed `` mentally incompetent '' to handle their finances from having their names entered into a national background check system , thereby blocking them from gun ownership . Instead , the Oklahoma physician wanted those case decided by a judge rather than a federal agency unless those veterans had been `` found by a judicial authority to be a danger to themselves or to others . '' `` We 're not asking for anything big , '' Coburn said at the time . `` We 're just saying that if you 're going to take away the Second Amendment rights -- they ought to have it adjudicated , rather than mandated by someone who 's unqualified to state that they should lose their rights . '' New York Democratic Sen. Chuck Schumer pushed back argued that `` you should not have a gun '' whether `` you are a veteran or not and you have been judged to be mentally infirm . '' National Rifle Association President David Keene said at a recent media event that his organization supports reforms that would make it tougher for mentally ill people to get guns . How the violent mentally ill can buy guns . Federal law makes it illegal to sell or give a firearm to anyone who `` has been adjudicated as a mental defective or has been committed to any mental institution . '' Statistics from the FBI 's National Instant Criminal Background Check System ( NICS ) show about 1 percent of applicants who failed a background check over the past 14 years , or 10,180 people , were turned down for reasons related to mental health . Overall rejections represented a fraction of prospective gun sales and most involved applicants with criminal records . Federally licensed gun shops must use the National Instant Criminal Background Check System , or NICS . Private sellers and gun shows have no background check requirement . But information in the national background check system is incomplete , particularly involving mental health records , investigations have found . Critics blame what they call a huge legal loophole , according to one study . `` PTSD is rarely associated with homicidal violence , '' Michael Welner , a forensic psychiatrist who has worked on cases of Iraq and Afghanistan veterans charged with violent crimes , told CNN 's Soledad O'Brien . `` PTSD is very commonly associated with a number of other conditions that are regularly attached to violence , alcoholism , personality disorder , depression . So diagnostically , PTSD may be relevant and it may just be part of the picture , including traumatic brain injury , '' Welner said . Expanding some background checks is under consideration in Congress as lawmakers respond to public and political pressure for stricter laws following December 's shooting massacre at a Connecticut elementary school . Possible steps include better monitoring of people with mental illness to prevent them from obtaining firearms . Mayors Against Illegal Guns aired an ad during the Super Bowl advocating universal background checks for gun sales . President Barack Obama also reiterated his call on Monday for comprehensive steps to address gun violence , including expanded background checks . Correction : Earlier versions of this report incorrectly described the military background of Chad Littlefield , who was killed with Chris Kyle . Littlefield was not a veteran . CNN 's Greg Botelho , Joe Johns , Jen Christensen and Josh Levs contributed to this report .
Former Navy SEAL who was shot and killed helped veterans with stress problems . Killing in Iraq raises new questions about mental health amid gun debate in Congress . Suspect , a civilian , told police last year he was suffering from post traumatic stress . Plans in Congress weigh expanding background checks , Obama calls for action on guns .