This is just me trying to come up with a plausible scenario for his release:
The public has been relying on media reports and eyewitnesses so far. First reports are always inaccurate in some way. Multiple people can see the same event and describe it completely differently. Some people also just lie to cops and the media for any number of reasons. So the media is working with that incomplete information in getting the initial stories out.
The sheriff's office said that the incident was the culmination of a road rage incident. The shooter fired all of the rounds while he was seated in his vehicle. In Louisiana, your vehicle is legally an extension of your home. If someone is trying to get into your vehicle to harm you or someone else, deadly force is legal just the same as if they were breaking into your home.