The video, captured on CCTV cameras, shows the suspect armed with an AR-15-style rifle standing outside of the store where he aimed his firearm at the windshield of a car and began firing rounds.
Police said the gunman, later identified by police as 21-year-old Ryan Christopher Palmeter, shot and killed one person outside of the Dollar General.
From there, cameras from inside the store showed the gunman walking in wearing a tactical vest, a face covering, a hat, ear protection and gloves.
He can be seen pointing his firearm in the direction of people where he later killed two other people. All three victims, Angela Michelle Carr, Anolt Joseph Laguerre Jr and Jerrald De’Shaun Gallion, were Black.
The gunman is thought to have died by suicide.
Authorities said they believe the shooter carried out a racially-motivated shooting where he specifically targeted Black people. They were able to determine this based on several manifestos that the gunman left behind.
“I know for a fact that he did not like Black people,” sheriff TK Waters of the Jacksonville Sheriff’s Office said in a press conference. “He made that very clear.”
Authorities said the gunman left behind a note and last will and testament for his parents in addition to the writings, intended for the media and federal agents, regarding his hateful ideology.
Mr Waters called the writings “sickening” and “the diary of a madman” saying many of his thoughts were “completely irrational” though clearly done with intention.
“He knew what he was doing. He was 100 per cent lucid," Mr Waters said. "He knew what he was doing and again, it’s disappointing that anyone would go to these lengths to hurt someone else."
The shooter did not have a criminal record but was held involuntarily in a 72-hour psychiatric evaluation in 2017 after a domestic dispute involving him and his brother – though this did not show up on his background check when he obtained his firearms legally under the Baker Act.
In photos of the firearms that the gunman used to kill the three people, one gun has swastikas drawn on it.