NASHVILLE — There is something fundamentally democratic about a Waffle House restaurant in the wee hours of the morning. It’s a place where people working the late shift can stop for a hot meal on the way home, where high school kids can extend prom night just an hour longer, where 20-somethings jazzed on live music can wind down after a night on the town. The coffee is always fresh, and the counter staff has heard it all before but will usually listen again if you need an ear. It’s a uniquely American place.

There’s something tragically, fundamentally American, too, about an angry young white man with a firearm killing a bunch of strangers who have done him no harm. That’s what happened early Sunday morning, when a man who was naked except for a green jacket loaded with ammunition opened fire with an AR-15 rifle at a Waffle House in the Antioch section of Nashville. Four people were fatally shot and four others were wounded before James Shaw Jr., an unarmed customer, wrestled the gun from him, saving untold lives.

The attacker ran away, shedding the jacket as he fled. Also left in his wake: Akilah Dasilva, DeEbony Groves, Joe Perez, and Taurean C. Sanderlin, all dead. All were in their 20s. All were people of color.

A search of the truck the gunman left behind led investigators to Travis Reinking, an Illinois man who had moved to Nashville only last fall. Considered armed and dangerous, Mr. Reinking immediately went to the top of the Tennessee Bureau of Investigation’s most-wanted list. After some 34 hours at large in a cold rain, he was apprehended Monday afternoon clothed and wearing a backpack containing a loaded semiautomatic handgun.