The Roanoke, VA incident took place in July, just one month before Flanagan murdered reporter Alison Parker and cameraman Adam Ward.
Brandon captioned the video, "I called this man out at a red light for driving like a maniac. He then followed me to my destination driving recklessly, and stopping traffic to continue the argument, the rest is on film."
In an interview with CNN, Brandon shared, "He was obviously not in the right mind. He was driving in excess of 100 mph."
Since the murder, more details are coming to light about Flanagan and his state of being. His family released a statement after the tragedy, saying, "It is with heavy hearts and deep sadness that we express our deepest condolences to the families of Alison Parker and Adam Ward. We are also praying for the recovery of Vicki Gardner. Our thoughts and prayers at this time are with the victims' families and the WBDJ7 NEWS family. Words cannot express the hurt that we feel for the victims. Our family is asking that the media respect our privacy.”