Family members say Ramon Garcia, a father of five, had gotten into an argument with a man Saturday afternoon at nearby Saint James Park.
In the surveillance video you can see Garcia get off his bicycle and back up against a car. The gunman chases him down and shoots the victim in the head.
Garcia's aunt, Patricia Lechuga, says her nephew was trying to turn his life around.
"I asked him if he was going to stay out of trouble, stay out of jail," she said. "And he said 'yeah tia, I'm gonna do good, I'm gonna try and do good this time and I'm gonna do it for me and my kids.'"
This was the city's 33rd homicide of the year.