It was growing light outside the basement window, even though it was only just gone half four in the morning. Two more days, then it would turn and start getting darker. It was the middle of summer and the days were at their longest, and yet he felt melancholic about it being downhill from here.

But that wasn’t the only reason he’d lain sleepless for hours and finally got up and trudged back down to the basement. His thoughts had revolved around Molander. Now that he’d found an opening in his Berlin alibi, there wasn’t much doubt left.

The problem was that despite all the hours he’d put in, he still didn’t have a shred of concrete evidence. None of the many things he’d uncovered and concluded came even close to being able to hold up in court.

He’d managed to fill in some of the gaps, true, and he’d collected enough material to make a strong circumstantial case. But no matter how strong it was, what he had was in no way tantamount to concrete proof.

It was like the Berlin alibi. He could show that there was a reasonable possibility Molander had in fact not been in the German capital when Inga Dahlberg was murdered. But as long as Gertrud insisted she’d been with him the whole weekend, he had nothing.

Hugo Elvin must have, though.

There could be only one reason Molander would have risked going so far as to off his colleague: that Elvin had found something incriminating enough to constitute a real threat. The question was where he’d hidden his evidence. Certainly not in his desk drawer, anyway.

Every time he’d gone through its contents, he’d been forced to conclude that all the clues, pictures and notes belonged to the category strong suspicion. Even so, he’d decided to go over it all again.

He put the pictures of Inga Dahlberg aside and took out Elvin’s diaries, flipping through them one page at a time, reading his brief and sometimes cryptic notes again. But they held nothing he hadn’t already looked into.

Finally, he took out the key ring with the seven keys marked with different-coloured cloth tape that divided them into groups. One of the three green ones, which all had handwritten question marks on the tape, had opened the locker at the Celluloid photography club that had belonged to Gertrud’s father, Einar Stenson. The other two were, indeed, still question marks. The same was true of the two white ones, one of which had a fish on its tape marker while the other had a code: 759583.