An 18-year-old Mississippi teen faces the prospect of spending the rest of his life behind bars after killing his neighbor.

But an attorney for DeShawm Douglas said the teen for months faced threats from his neighbor, 54-year-old Christopher Miln, and even filed assault charges against the man.

That case was not prosecuted, but Miln was ordered to stay away from Douglas, according to a statement from Scott Gilbert, the teen’s lawyer. Gilbert claims Douglas acted in self-defense when he took deadly action, citing a cellphone video that showed the two men scuffling outside of Douglas’ home moments before the fatal shooting.

“Shawn and his family had been victimized by Miln’s threats of violence for months,” Gilbert wrote. “These threats were not only directed at Shawn, but at his 13-year-old baby brother. The publicly available video evidence from Dec. 28 is clear.”

Douglas was captured in the parking lot of a Regions Bank in Brandon, Mississippi, on Dec. 28 after a brief manhunt, according to WAPT News. He was charged with first-degree murder.

The shooting occurred that afternoon near Douglas’ residence, which was just around the corner from the bank at which officers apprehended him. According to the Rankin County Sheriff’s Office, deputies were dispatched to the area of Brendalwood Lane and Bay Park Drive at 3:15 p.m. and found Miln shot multiple times.

Investigators learned that Douglas and Miln were in a physical fight and Douglas pulled out a gun and shot his neighbor before fleeing on foot.

Multiple agencies worked in tandem to track Douglas down by 6 p.m. Miln, who suffered four gunshot wounds, was rushed to the University of Mississippi Medical Center, where he later died.

One man who witnessed the incident recorded the fight and argument between Douglas and Miln that led to the shooting. The video seemed to show Miln antagonizing Douglas as the teen stood on his front porch. The two could be heard trading verbal threats. At one point, Miln told Douglas, “I’m on your property” then challenged the teen, saying “C’mon, let’s go.”

Douglas, in the video, alleged that Miln threw mud on him and spit in his face.

“I really should’ve hurt you, bro’, but I’m not going to do it,” he’s heard telling Miln at one point.

Miln then lunged at Douglas and gave chase when Douglas walked toward his backyard. The sounds of a fight could be heard off camera. Moments later, Miln is seen wrestling Douglas to the ground and the two men tussled. One man who tried to intervene told Miln “you’re drunk as f–k” and tried to get him to let Douglas go before the video ended.

Brandon Warren, who recorded the footage, told WAPT, an ABC News affiliate, that Douglas pulled out a gun and opened fire shortly after the scuffle was broken up.

“Shawn walked away from Miln, just like he had done several times before,” Gilbert said in his statement. “For reasons known only to Miln, he finally decided to make good on his threats and he violently attacked Shawn, grabbing Shawn from behind, wrapping his arm around Shawn’s neck and wrenching downward in an effort to cut off Shawn’s ability to breath.”

The attorney detailed a history of strife between the two men that dated back to early October. He said Douglas tried to have Miln prosecuted for brandishing a shovel and threatening him with it. A simple assault charge, for which Miln faced 180 days in jail, was remanded and he pleaded guilt to criminal trespassing, court records show. A judge ordered Miln to have no contact with Douglas but spared him any jail time.

Gilbert said Douglas’ mother has also called local authorities on Miln, but he said none of the family members “ever allowed Miln to provoke them into a physical altercation.”

Rankin County Sheriff Bryan Bailey told WAPT their appeared to be some bad blood between the two neighbors.

“From the best I can tell right now, this has been an ongoing feud or argument,” the sheriff said.

Douglas was released from jail on $75,000 bond on Jan. 4 and his case must now go before a grand jury, the TV station reported.

A Tupelo, Mississippi homeowner fatally shot his neighbor in the chest in June 2013 when he spotted the 41-year-old man on his back patio. Local police deemed it a home invasion, determining the homeowner fired in self-defense. A grand jury agreed, and no charges were ever filed, according to News Mississippi.

The case raised questions about what constitutes a justifiable homicide in Mississippi. Magnolia state lawmakers in 2006 passed one of the nation’s broadest castle doctrine laws, giving Mississippians wide latitude to legally use deadly force.

According to the state’s justifiable homicide law, there are nine scenarios under which homicide is legally warranted. Residents can use deadly force to lawfully defend themselves in cases of imminent danger and while resisting someone’s “attempt to unlawfully kill” or “commit any felony” upon them.

A person who uses deadly force has no duty to retreat before doing so but must have “reasonably feared imminent death or great bodily harm,” the statute goes on to state.

Gilbert said Douglas was acting reasonably when he shot Miln, given his neighbor’s past behavior.

“Every Mississippian has both an inherent and a legal right to use deadly force to defend themselves from someone who is attempting to cause great personal injury,” the attorney’s statement indicated. “Shawn’s actions on Dec. 28 were reasonable under the circumstances. Even though Shawn was able to momentarily free himself from Miln’s lethal grip, there was nothing preventing Miln from continuing to pursue his attempt to injure Shawn.

“While Miln’s death is tragic, it was the legally justifiable consequence of his violent attack on Shawn and the certainty that Miln would continue to escalate his violent behavior until Shawn or a member of his family were eventually killed,” Gilbert stated.