When law enforcement knocks on your door, it's always a bad idea to open the door with a gun in your hand. WTF was he thinking? If you have to answer the door, don't show your gun! From the OP's link..
"Once on scene, officers mistakenly approached" the wrong address and knocked on the door. The statement from the state public safety authority said the officers identified themselves as police, but no one answered."
"The statement said officer body camera video shows that as the officers backed away from house, the homeowner opened the screen door armed with a handgun. One or multiple officers fired at least one round, striking the homeowner, who police identified as 52-year-old Robert Dotson."