Bradley Dermond, the couple's son, described his parents Wednesday morning as "salt of the Earth."
"This absolutely makes no sense at all," Bradley Dermond told 13WMAZ Wednesday morning while driving up from Florida to be briefed by law enforcement about the case.
"We're still hoping that our mother is OK," he added declining further comment until he speaks with law enforcement.
Russell Dermond was found dead Tuesday morning in the garage of his home in Lake Oconee.
Sheriffs officials are searching for his wife, Shirley Dermond, 87, who they believe may have been kidnapped.
An autopsy will be performed Wednesday on Russell Dermond, Sills said.
Friends called the sheriff's office after they hadn't heard from or seen the couple in several days.
Sills wouldn't comment further as to how Russell Dermond was killed, but said he was "definitely the victim of a homicide."
When officials couldn't locate Shirley Dermond, Sills said, "their vehicles are at home. We are treating this as if (Mrs. Dermond) has been abducted."
The sheriff said he believes Mrs. Dermond is "in imminent danger."
Deputies believe the crimes occurred between Friday and Sunday.
Sills said there apparently was no surveillance video in the neighborhood.
"I've been a police officer for 40 years, and of course, I've worked many homicides. I've never had (a case) where one party to the home was not there, and the body of the other party was there," Sills said,
Shirley Dermond is 5'2", weighs 148 lbs. and has grey hair and blue eyes.
Investigators asked anyone who may have seen Shirley Dermond or who has information on the case to call the Putnam County Sheriff's Office at 706-485-8557.
Roy Dunning has lived on the same street as the Dermonds for 11 years. While he didn't know them very well, he said "they were very, very nice. ... They were quiet people ... Russell walked a lot."
Dunning, who lives two doors down from the couple, said he noticed police tape on the Dermonds' home Wednesday morning. "It shocked me," he said. "Everyone is in a state of shock, especially for Shirley."
Meanwhile, the couple's pastor described them as a '"sweet couple ... unassuming ... family oriented."
"We were all in shock and we really just don't know how they'd have any enemies or anybody who'd want to do anything to them," said the Rev. David Key of Oconee Lake Community Church. "They're the last couple that you would think anybody would break in and do this kind of violence to."
The Rev. Key said the couple had attended the church for about seven years, as recently as Easter Sunday.
According to Putnam County tax records, the Dermonds' home and property on Carolyn Drive is valued at over $1 million. It includes a boat dock on Lake Oconee.
According to online records, the home is in Reynolds Plantation's Great Waters gated community, built around a Jack Nicklaus-designed golf course.
They purchased the land in 1994, according to tax records.