“I can see his point. Where did your sister go on vacation?”

“She didn’t say. Up north someplace. Someplace she and Mr. Riggs like to go to, to…you know. To get away?”

I called Sgt. Pribyl from a gas station where I was getting Barney’s Hupmobile tank re-filled. I suggested he have another talk with bartender Alex Davidson, gave him the address of “Mr. and Mrs. Riggs,” and told him where he could find the maroon Plymouth.

He was grateful but a little miffed about all I had done on my own.

“So much for not showboating,” he said, almost huffily. “You’ve found everything but the damn suspects.”

“They’ve gone up north somewhere,” I said.

“Where up north?”

“They don’t seem to’ve told anybody. Look, I have a piece of evidence you may need.”

“What?”

“When you talk to Davidson, he’ll tell you about a matchbook Rooney wrote the girl’s number on. I got the matchbook.”

It was still in my pocket. I took it out, idly, and shut the girl’s number away, revealing the picture on the matchbook cover: a blue moon hovered surrealistically over a white lake on which two blue lovers paddled in a blue canoe-Eagle River Lodge, Wisconsin.

“I suppose we’ll need that,” Pribyl’s voice over the phone said, “when the time comes.”

“I suppose,” I said, and hung up.

Eagle River was a town of 1,386 (so said the sign) just inside the Vilas County line at the junction of US 45 and Wisconsin State Highway 70. The country was beyond beautiful-green pines towering higher than Chicago skyscrapers, glittering blue lakes nestling in woodland pockets.

The lodge I was looking for was on Silver Lake, a gas station attendant told me. A beautiful dusk was settling on the woods as I drew into the parking of the large resort sporting a red city-style neon saying, DINING AND DANCE. Log-cabin cottages were flung here and there around the periphery like Paul Bunyan’s tinker-toys. Each one was just secluded enough-ideal for couples, married or un-.