I found a spot on the second floor of a parking garage and, as soon as the coast was clear, hustled Sally into his crate. My heart was pounding as I ran down the stairs and through the back entrance of the casino. The place was packed with gamblers hovering over blackjack tables and slouched in front of slots. A celebration broke out at a craps game, clapping and whistling and shouts of “Attaboy” and “Keep ’em coming,” and waitresses dressed like Old West saloon girls chanted, “Cocktails, cocktails.”

I squinted through the cigarette smoke for the blonde, found her posing at the bar. The bartender set a drink in front of her and she reached for her purse, but the guy sitting beside her, a balding, paunchy white man in a cheap suit, laid a hand on her arm. “Pretty ladies drink for free when Mark Arcamonte’s around,” he said. He and the woman began to flirt.

I sat at a nearby slot machine and eavesdropped on the man’s life story, or at least the version he told women he met in bars: Illinois, insurance, top salesman, only the best for him. He took out his wallet and showed the blonde photos of his car and his boat. When he flipped to a picture of his kids, he kept his thumb over the face of his ex-wife, who was also in the shot. “You don’t want to look at her,” he said. “You’ll turn to stone.”

The blonde laughed when she was supposed to, offered sympathy when Arcamonte asked for it, and thanked him for the free drinks with cheek kisses and cuddles. Finally, though, it was time to close the deal.

“This has been fun and all, but you know I’m on the clock, right?” she said.

“Sure, sure, I get that,” Arcamonte replied.

“So what now?”

“Let’s get the hell out of here.”

I tailed them as they walked out of the casino and east on Fremont. The crowds disappeared after a few blocks, casinos giving way to liquor stores, pawnshops, and budget motels. The blonde and Arcamonte turned into the parking lot of a low-slung dump called the Sky Harbor Inn. I caught up in time to see them step into Room 104 on the ground floor.

It hit me that Arcamonte might be the blonde’s next victim instead of a customer. I crossed the street, sat on the curb, and pictured her talking dirty to him, nuzzling his ear, then pulling a knife to cut his throat. God was kind to the man, however: An hour after he went into the room with the blonde, he left alone and slunk back toward Glitter Gulch.

Fifteen minutes later the blonde came out. She walked two doors down, to Room 106, and used a key to let herself in. It was 2 a.m. I kept watch until 5, but she never reappeared.