MIAMI -- Cell phone video captured outside of the Publix in Oasis Plaza Saturday night shows the final moments of 44-year-old Alexander Arrington's life.
In the video, Arrington is seen shooting a car multiple times.
Police say that's what led to him being confronted by a security guard and eventually Homestead Police.
The situation escalated and an off-duty, 30-year veteran, Miami Dade Police Officer identified as Francisco Moreno, intervened.
"This officer is sitting with his family, he's in the car waiting while his family is in there shopping, and he hears gunfire and it just goes back... you never know where it's going to happen," said Steadman Stahl, president of South Florida PBA.
In the video, Moreno orders Arrington to drop his weapon multiple times.
Arrington repeatedly says he's going home.
After that exchange, Moreno shoots Arrington.
He was airlifted to Jackson Memorial South where he later died.
"He's not a violent person, he's a quiet guy. I don't know, for me, it's like really sad because he's really young and I've never seen him do nothing wrong," said Jaina Rodriguez-Tamayo.
Rodriguez-Tamayo was Arrington's next-door neighbor.
She says he was a quiet but friendly and helpful neighbor and was shocked to see what happened to him.
"He has kids. The other thing is he's having mental problems, and he just got out from the hospital the day before that incident," said Rodriguez-Tamayo.
According to police, this isn't Arrington's first run-in with the law. In July, he was arrested and charged with aggravated assault with a weapon and two counts of strangulation.
Stahl says when it comes to Saturday's incident, the off-duty officer did the right thing by getting involved.
"There may be a mental aspect to this, but that officer would of had no way of knowing what his mental state was, whether he was mentally ill, whether he was out to hurt somebody but he was certainly armed with a firearm and he was there engaging people with it," said Stahl.
Neighbors also told CBS 4 that Arrington was a veteran and it's still unclear why he opened fire.
Moreno is currently on administrative leave with pay as the Florida Department of Law Enforcement investigates the shooting.
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