On February 2, 2013, Chris Kyle, a former US Navy SEAL, was tragically shot and killed at age 38 by ex-marine Eddie Ray Routh.

Kyle and his friend, Chad Littlefield, were fatally shot a total of 13 times using guns that Kyle had provided to Routh for use at a shooting range they were visiting together.

Though Kyle reported 255 kills during his combat service, the US Department of Defense has officially confirmed 160 of these.

Chris Kyle's life story became the basis for "American Sniper," an Oscar-winning film directed by Clint Eastwood, featuring Bradley Cooper in the lead role as Kyle.

After serving in Iraq and assisting after the Haiti earthquake, Routh was diagnosed with PTSD. He had received treatment at a veteran's hospital intermittently before his mother reached out to Kyle, hoping he could assist her son in dealing with his trauma.

Kyle, who also struggled with PTSD, organized events where veterans could bond over activities like hunting or shooting. Routh's mother was acquainted with Kyle, as their children attended the same school.

Deciding to help, Kyle and Littlefield invited Routh for a shooting session at Rough Creek Lodge. That's where the unfortunate incident took place.

On their way to the shooting range, with Kyle driving, Littlefield beside him, and Routh seated behind, tension was palpable. Both Kyle and Littlefield seemed uneasy about Routh's presence.

Evidence from the trial revealed that during this drive, Kyle texted Littlefield saying, "This dude is straight up nuts." Littlefield responded with, "He's right behind me, watch my six," a military term asking someone to cover their back.

When the authorities later apprehended Routh, he reportedly complained that the two men "wouldn't talk to me".

A forensic psychologist, after interviewing Routh in prison, deduced that Routh believed Kyle and Littlefield had intentions to harm him, given the number of firearms they had with them.

Even with their evident apprehension about Routh's demeanor, Kyle and Littlefield proceeded to the shooting range, where the tragedy unfolded.

During his trial, Routh admitted to shooting Littlefield first, with seven bullets hitting him in various parts of his body, including the back, shoulder, head, and hands. Kyle was subsequently shot six times, with injuries to his head, chest, shoulder, and arm.

Routh, at his trial, entered a plea of not guilty due to insanity. However, the jury convicted him, and he was handed a life sentence without the possibility of parole.