The Madison County Sheriff's Office — which took over the investigation because a family member of the homeowner is a part-time Collinsville police employee, the station said — determined that the homeowner asked Gagen leave the residence's front porch, but Gagen refused.
The homeowner feared for his safety and got a gun from inside the home while making "numerous" requests for Gagen to leave, KDSK noted.
The homeowner also told Gagen to not enter the home, but Gagen opened the storm door and said the homeowner would have to shoot him, the station reported, citing the sheriff's office.
With that, the homeowner fired one shot, KDSK said, adding that it struck Gagen in the chest.