UPDATE: A Rossville man has been charged with murder in Wednesday's fatal shooting of Jeremy Little, 33.
Rossville police said Robert Ellis Jr, 44, shot little in the head in the backyard of Little's home.
Family members told police the two men had been arguing back and forth for several days.
Detective David Scroggins said the feud between Little and Ellis started at the Dollar Tree days before, but it was a case of mistaken identity.
Det. Scroggins said Ellis approached Jeremy Little's girlfriend as she was walking out of the store and harassed her, thinking she was another woman.
"She went home and told Mr. Little about the encounter, Mr. Little and Mr. Ellis had known each other for a long time," Scroggins said, "He said, 'Stay away from my girlfriend.' 'I don't have to stay away from your girlfriend,' an argument ensues."
Det. Scroggins said the fighting went back and forth, each smashing out each others' truck windows and posting threatening comments on Facebook.
"It just escalated to the point where Mr. Ellis thought it necessary to go shoot Mr. Little," Scroggins said.
Little was shot in the head in his backyard on State Line Road.
Family members told police Ellis had come over to continue the argument. This time, he brought out a gun.
"Stupid stuff, stupid people involved with methamphetamine," he said.
Det. Scroggins said Ellis admits to using drugs, and was high on meth when he mistakenly took Little's girlfriend for someone else.
Scroggins said he's certain little's death could have been prevented.
"If you have a dispute with a friend or a neighbor a gun is never the answer, if you have an issue over property damage, call the police," Scroggins said.
Robert Ellis is charged with murder, aggravated assault, illegal possession of a firearm and other charges in the death of Jeremy Little.
PREVIOUS STORY: The Rossville Police Chief said 33-year-old Jeremy Little was killed Wednesday afternoon when he was shot in the head by another man.
Chief Sid Adams said the call came in around 1:30 p.m. on a person shot call at 408 State Line Road in Rossville. A family friend said the two men had been arguing for several days, partly because of a Facebook post, which is could have led to the shooting. Detectives say Jeremy Little was shot in the head once in his backyard.
On the scene in Rossville where a man was shot in the head. Rossville PD investigating. Man taken to hospital, condition unknown. @WRCBpic.twitter.com/AldDAAGUAX