NORCROSS, Ga. (AP) _ A gunman shot four people to death inside a Korean health spa in Atlanta’s suburbs and then killed himself in what police said may have been a case of domestic violence.

Surveillance video showed a man walking into the Su Jung Health Sauna on Tuesday night and getting into an argument with someone, then opening fire, police said.

“It appears he walked in, had some conversation with one of the victims and the shooting started,” Norcross Police Chief Warren Summers told WAGA-TV.

Investigators had finished interviewing witnesses Wednesday morning, Norcross police Capt. Brian Harr said. He described the shootings as “not random.”

“It’s probably domestic-related,” Harr told The Associated Press, adding that more information would likely be released later Wednesday.

Yellow police tape surrounded the stand-alone brick building early Wednesday on a busy highway lined with strip malls and small businesses.. The spa’s decorative white columns and white Greek-style statuary faced a parking lot empty except for a handful of police and official vehicles. The spa was closed.

Police said the dead were three men and two women. Four people were found dead inside, and another was taken to a hospital before being pronounced dead, investigators said.

Investigators say they believe about 20 people were inside the spa when the gunfire began around 8:30 p.m.

The Georgia Bureau of Investigation joined the probe, GBI spokesman John Bankhead said.

“We actually sent two crime scene specialists, given the situation out there with the number of people who were shot and killed,” Bankhead said.

He said investigators were using 3-D technology that was designed for architecture and construction jobs and is now being used in some investigations to recreate crime scenes.

The spa is about 15 miles northeast of downtown Atlanta, on Buford Highway between Peachtree Industrial Boulevard and Interstate 85 in Gwinnett County.