Hundreds of lawsuits have been filed against the owner of the resort where the gunman opened fire into an outdoor concert on Oct. 1, 2017.
In the two years since the deadliest mass shooting in modern U.S. history, the federal government and states have tightened some gun regulations.
Officers in Amarillo, Texas, went to the home of Seth Ator's mother in February 2011 after she told them he had refused to take his mental-health medication and had threatened to end his own life in a shootout with police.
Most mass shooters in the U.S. acquired the weapons they used legally because there was nothing in their backgrounds to disqualify them, according to James Alan Fox, a criminologist with Northeastern University who has studied mass shootings for decades.
Texas lawmakers have spent five years fighting for the victims of the 2009 Fort Hood shooting.
Security alerts immediately went up across the globe after the attack in Paris.