Police were interviewing witnesses at a spa outside Atlanta where a gunman opened fire, killing five people in what authorities described as a murder-suicide.
Surveillance video shows a man walking into the spa 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 Atlanta television station WAGA.
Four people were found dead inside, and another was taken to a hospital before being pronounced dead, Norcross police Capt. Brian Harr told the Gwinnett Daily Post. Police described the dead as three men and two women.
Investigators say they believe about 20 people were inside when the shooting began around 8:30 p.m. Tuesday at the Su Jung Health Sauna in Norcross.
The Georgia Bureau of Investigation is working with local police on the case.