When officers arrived at the scene, they found the employees on top of the middle-aged man, according to a police report obtained by ABC News affiliate WSB-TV. When an officer bent down to handcuff the suspect, he noticed there was no resistance.
At that point, the officer noticed the suspect was bleeding from the nose and mouth, according to the report. He was transported to DeKalb Medical-Hillandale Hospital, where he was pronounced dead.
"This is truly a sad situation," Dianna Gee, a Walmart spokeswoman, said in a statement issued to ABC News. "We don't know all of the facts right now. We're in the process of working with law enforcement to determine all of the facts and cooperating and providing any information we have to assist in the investigation."
Gee said the contract security guard will no longer be providing services to the retailer. The two store employees have been suspended with pay while Walmart assists police in the investigation.
ABC News' Dan Milano, Alyssa Newcomb, Susanna Kim, ABC News Radio and The Associated Press contributed to this report.