Robert Aaron Long & The Massage Parlor Massacre: An anthology of True Crime

At 4 p.m. on March 16, 2021, a black 2008 Hyundai Tucson was caught on surveillance cameras entering a strip mall in Acworth, Cherokee County, Georgia. For about an hour, the car remained parked outside Young's Asian Massage, with the driver still in the car. At 4:50 p.m., the driver - a young man wearing black pants and a black-and-magenta hoodie - exited the car and walked to the door of the massage parlor which had the following sign posted on the door: "If you have cold or flu symptoms.
Wait for your massage at a later time. We are attempting to avoid the spread of any virus. Sorry for any inconvenience and please understand our position with this." Rita Barron, the owner of the business next to the massage parlor - Gabby's Boutique - was helping customers when she heard something like "pah pah pah" followed by women screaming. Believing that they must have dropped something heavy, she didn't pay any more attention to the noise.
However, her husband Alex Acosta was more suspicious of the noise. Wondering whether an animal might have wandered into the store and was causing the ruckus, he went outside, where he came across three workers from the massage rushing out of the business. He tried to get them to tell him what was happening, but communication was difficult because their English was poor. However, he managed to understand the core message - there was man with a gun and people had been shot.
Urging them not to head back to the parlor, Acosta rushed back inside the boutique and told his wife to call 911. Cherokee County dispatched first responders to Young's Asian Massage, where officers found bloody scene inside the store. Acosta watched as two Asian women were carried from the parlor and placed on the pavement outside, while two other people were being treated inside. A few moments after police and ambulances arrived at the scene, Acosta stated that a man with blood between his eyes walked at least five steps before he collapsed on the ground...
What in the world was happening and who was behind all of this chaotic violence?