Details aren't clear yet, he may have been concealed carrying (legally?) and during the struggle agents saw the weapon in his waist, one alerted the other agents, gun! and then a moment after he was disarmed by one agent, another agent opened fire due to the ongoing struggle and not knowing the suspect had by that time been disarmed, so expect things to get more tense.
Old video from probably the 90s is now circulating showing Pantera's singer endorsing White Pride and denouncing antiwhiteism (he called it reverse discrimination, which was a common term used back then for it)