SUTHERLAND SPRINGS, Texas -- The killer wore a bulletproof vest and a face mask with a white skull on it.
Devin Kelley had a history of domestic violence on his military record that should have barred him from owning guns, but he was armed with a 5.56-mm Ruger semiautomatic rifle that he was allowed to buy because of a bureaucratic error by the U.S. Air Force.
By contrast, his adversary, Stephen Willeford, was barefoot.
Willeford was at home Sunday in Sutherland Springs when his daughter first heard the shooting next door at the First Baptist Church, and he went over to see what was happening. He had friends inside.
A former National Rifle Association instructor, Willeford took with him the AR-15-style assault rifle that he keeps in a safe.
What happened next was a scenario nearly unheard of in mass shootings, but one often suggested by those in favor of a well-armed citizenry: An armed bystander got in a shootout with a mass killer, and chased him out of town.
Two of Willeford's shots apparently hit Kelley, one in the leg, and one in the torso. The gunman dropped his gun and fled the scene in an SUV.
Willeford had been brave enough, and he had been skilled enough. But he had not quite been fast enough. Back at the church, Kelley had already killed 26 people and wounded 20 more, including many children, in the fifth-deadliest shooting in modern American history.
On Monday, as more details about the shooting became clear, the gunman and the Good Samaritan seemed to increasingly represent the two poles of the nation's political debate over gun control and gun ownership.
On one end of the political spectrum, Willeford seems to embody the NRA's axiom that "the only thing that stops a bad guy with a gun is a good guy with a gun" -- the argument that the best defense against mass shootings is a better-armed and better-trained civilian populace, ready to defend itself, anywhere, at a moment's notice.