When the 26-year-old got back to his Greenville home with his family, authorities say they were attacked by gunmen.
Police say between three to five gunmen held him at gunpoint, tied up his girlfriend and eight-year-old daughter, then ransacked the house looking for valuables.
His sister and mother asked WTVM not to reveal their identities but described how the kidnapping played out.
"He walked in with his hands up and said just do what they tell you to do. Another person brandished two guns and told her to get on the floor and not to look at him and if you do what we say, we won't hurt you. They said, he's got to go for a ride with us and if we don't see any blue lights, you don't call the police, then he'll be returned to you this evening," Louder's sister said.
But that never happened. Louder was found dead inside his car the next day along a rural Troup County road. Investigators say he was driven there by his attackers and shot several times.
"Right now, we're interviewing people and trying to come up with a suspect or develop a lead in this case. At this time, no arrests have been made, no suspects have been developed yet," said Sergeant Chad Mann with the Troup County Sheriff's Office.
"They took my baby. They took my only son. No money is worth someone's life. I'm praying for peace and most of all, I want justice," Louder's mother said.
"We believe that justice will be served through God and He'll take care of whoever took my brother's life," his sister added.
If you have any information that could help the GBI solve this case, call the GBI Region 2 Columbus office at 706-565-7888 or the Troup County Sheriff's Office at 706-812-1000 or the Troup County Crime Stoppers hotline at 706-812-1000.
Funeral arrangements for Louder are tentatively set for this weekend.
A visitation is set for Friday, January 8th from 6-8 PM at Saint Mary's Church in Hogansville.
The funeral is scheduled for Saturday the 9th at 11 AM at Mount Venus Baptist Church in Gay, GA.