WATER STREAMED from fire hoses, dousing flame. Metal sizzled and the air turned rancid.

I found Chuck Hanni, arson investigator and explosion expert, stooping outside the school bus’s side door. He had his hair slicked back, and he wore khakis and a denim shirt, sleeves rolled up, showing the old burn scar that ran from the base of his right thumb to his elbow.

Hanni looked up, said, “God-awful disaster, Lindsay.”

He walked me through what he called a “catastrophic explosion,” showed me the two adult-size “crispy critters” curled between the double row of seats near the driver’s side. Pointed out that the bus’s front tires were full of air, the back tires, flat.

“The explosion started in the rear, not the engine compartment. And I found this.”

Hanni indicated rounded pieces of glass, conduction tubes, and blue plastic shards melted into a mass behind the bus door.

“Imagine the explosive force,” he said, pointing to a metal projectile embedded in the wall. “That’s a triple beam balance,” he said, “and I’m guessing the blue plastic is from a cooler. Only took a few gallons of ether and a spark to do all this…”

A wave of his hand to indicate the three blocks of utter destruction.

I heard hacking coughs and boots crunching on glass. Conklin, his six-foot-two frame materializing out of the haze. “There’s something you guys should see before the bomb squad throws us outta here.”

Hanni and I followed Conklin across the intersection to where a man’s body lay folded up against a lamppost.

Conklin said, “A witness saw this guy fly out of the bus’s windshield when it blew.”

The dead man was Hispanic, his face sliced up, his hair in dyed-red twists matted with blood, his body barely covered in the remnants of an electric-blue sweatshirt and jeans, his skull bashed in from his collision with the lamppost. From the age lines in his face, I guessed this man had lived a hard forty years. I dug his wallet out of his hip pocket, opened it to his driver’s license.