Cops were at a loss to explain why Jeremiah Fogle, 57, who ran a Christian ministry at his home with his wife Theresa, 56, would suddenly flip out and kill her.
Her sister Maria Beauford said they had run their own transportation business together and that he had been sick over the past year and needed back surgery.
But she said that her sister had nursed him back to health and they had always been smiling at family gatherings.
She added:"We have no idea what his motive was. We just have no idea."
Is brother Collis added: "It's so sad. I've been trying to call to figure out what went wrong."
It was unclear if he had any grudge against Pastor William Boss and the Associate Pastor Carl Stewart, both of whom remain critically injured after the shooting.
Cops said Fogle bent down as if to identify Boss, then shot him once in the back of the head, before shooting Stewart, three times.
Two parishioners, Derrick Foster and Corey Reed, tackled Fogle. They held him down and took away his gun, a 32. caliber revolver, until law enforcement could arrive to arrest him.
Sheriff Grady Judd called them heroes.
He told WTSP: "We don't know what he would have done if not for the heroic actions of the people in the church to fight him to the ground and disarm him. That is a hero."