“What do you think?” Ringmar asked.

“Not so much to think about.”

“It’s like he was embarrassed.”

“For not having called us about the letter sooner?” Winter asked.

“You know I’m talking about something else.”

“It’s outrageous that people still have to keep this kind of thing secret even though society professes to be so tolerant.”

“Maybe there’s another letter somewhere.”

“Another letter that tricked Geoff into coming to Gothenburg? I’ll believe that when I see it.”

Ringmar pointed to the report. “Meeting somebody online-is that common these days?”

“That’s what I’ve heard.”

“He couldn’t really explain why they had switched to regular mail.”

“Yeah, I noticed that.”

“Maybe they thought it was safer.”

“Could be,” Winter said. “It lent the whole exchange an old-fashioned air of secrecy.”

“We’ll have to keep this guy in mind and hope something else turns up.”

“I’ve been thinking about why we didn’t find a letter from him in Geoff’s dorm room. He had no reason to throw it out, did he?”

“No.”

“Where is it, then?”

“Maybe he wasn’t the kind who saves letters.”

“A letter from a boyfriend who was one of the main reasons he came to Gothenburg? I’d bet anything he kept it, but somebody else got their hands on it.”

“Why would anyone else be interested?”

“Because something in it was incriminating.”

“Incriminating about what?”

“That’s what I’m trying to figure out.”

“So Hitchcock took it?” Ringmar asked.

“Right.”

“Because something in it would give us a lead?”

“I don’t know.” Winter reached for his cigarillos but remembered where he was. Ringmar hated it when the smell of smoke filled his office long after the culprit was gone.

“We’ll talk to this guy again, but not right away,” Ringmar said. “I was thinking about the flights between London and Gothenburg the other night. The passenger lists we requested have started to arrive now, and we need an extra office to go through all of them, not to mention more staff.”

“Lists for the past three months?”

“Right.”

“How long do the airlines keep them?”

“Two years for the flights out of Gothenburg.”

“Two years?”

“It’s a shot in the dark, Erik.”

“How many daily departures between London and Gothenburg?”

“Five round-trips on weekdays. The first is Scandinavian Airlines at 6:10. A.M. and the last is British Airways at 5:45 P.M. Then there’s an extra Scandinavian Airlines flight out of Gothenburg at 5:50 on Sunday morning.”

“Not all go to Heathrow, do they?”

“British Airways has a 7:15 A.M. flight to Gatwick.”

“That’s right, I was on it once.”

“You have one of those travel passes, don’t you?”

“I used to.”

“Every flight between Gothenburg and London carries a hundred to a hundred and twenty passengers.”

Winter nodded.

“Guess how many that makes in a year.”

“I don’t have my pocket calculator on me.”

“Somewhere around four hundred thousand.”

“That many?”

“Yep.”

“But we’re limiting ourselves to three months,” Winter said.

“That’s still too much work.”

“Any period we choose is going to be too much work.”

“Assuming we find the time,” Ringmar said, “I suggest we start with the flights the victims took. Then go backwards week by week. But we still don’t have the lists from London for the departures to Gothenburg.”

“I guess we’ll have to do it the way you suggest.”

“We’re still talking about a hell of a lot of passengers.”

“The lists show each passenger’s final destination, right?”

“I don’t know yet.”

“I hope so,” Winter said. “That way we can cross out those who left from Gothenburg but had connecting flights to Blackpool, Cape Town or wherever.”

“Assuming they weren’t pulling a fast one.”

“I’m trying to be a little constructive here. We both know what an impossible task this is.”

“Sorry.”

“So that leaves the passengers who flew round-trip between London and Gothenburg.”

“On their own passports.”

“Right.”

“The airlines check each ticket against the passenger’s passport, but if you have a fake one…”

“So all we have to do is identify everyone who flew on a valid passport. It’s a simple process of elimination. Then we nab the others.” Winter smiled.

“We can start with those who flew back and forth within a few days-say, a week or so.”

“Now you’re being constructive.”

“Constructive idiocy.”

“We’ll rule out as many passengers as we can. Somebody’s got to do it.”

Ringmar scratched his arm. “Maybe it’s constructive to track down the murderer this way,” he said finally, “but I’m not as convinced as you are.”

“I’m never convinced.”

“We have no evidence that the murderer commuted between Gothenburg and London. We don’t even know how many murderers we’re looking for.”

There was nothing for Winter to say. The role of investigators was to try out different theories one by one, occasionally several at a time. They didn’t let go of a hypothesis until they ran into a dead end, and even then they didn’t discard it entirely.

“All three murders were similar,” Ringmar said, “but there are plenty of possible explanations other than that it was the same guy.” They had already hashed this out a hundred times.

We have no choice but to plod along, Winter mused. We think out loud, and suddenly somebody comes up with something that hasn’t yet been said and we pounce on it. “They were paid to do it, is that what you mean?” he asked.

“Could be.”

“But what was the purpose?”

“The profit motive. I could be wrong, but I really think someone was out to make a movie.”

“We haven’t found any link between the three kids,” Winter said.

“Except that they might all have been homosexual or bisexual.”

“But we can’t even be sure about that.”

“Perhaps they never had the chance to find out themselves.”

“But at least it’s something they had in common.”

“Maybe.”

“And it might have been the cause of their deaths,” Winter said. “Indirectly at first, and then as directly as could be.”

“What do you mean by that?”

“Curiosity about something that was secret or forbidden got the better of them, and that’s what made them let a stranger into their apartments.”

“There might have been another reason.”

“Like what?”

“What could persuade you to let a stranger in?” Ringmar asked.

“Lots of money?”

“No.”

“A movie contract?”

“Try again.”

“A case of whisky?”

“You’re getting warmer.”

“Somebody I knew.”

“Bingo.”

They sat there silently.

An angel flitted through the room.

“You’re giving me goose bumps,” Winter said.

“Somebody they knew.”

“It’s certainly possible, but I’m skeptical somehow.”

Ringmar tried to weave together the various strands of the conversation in his head.

“I’m pretty sure there’s only one murderer,” Winter said. “He’s been here and there, and he’s here or there now too. Gothenburg or London.”

“We look for this person in the victims’ past. If he’s there, we grab him.”

“That’s not where we’re going to find him. Not in their past.”

“The past and the present, where do you draw the line?”

Winter had no answer.