He felt guilty reading what were in some cases the inner thoughts of a young woman on the people in her life and the emotions they caused in her, but often her words were so cryptic he could only guess, and he preferred not to. He imagined what he would have felt, had he ever committed his own thoughts to paper like this, and some mere stranger had read them.

He found the letter from Emma almost at the end. It was in the same cramped backhand as the one he had destroyed. It was far less specific, only words of any general sympathy, as if in answer to a letter from Katrina which did not need repeating for her responding emotions to be understood.

He read it twice, then folded it up again, put it in the diary and then put the diary carefully in his pocket. Apparently, Runcorn had not found it so he would not now miss it. He could read it later, and see if anything in it would lead to Emma.

Within half an hour of going in, he was out in the street again, telling the constable that unfortunately he had found nothing, and then wishing him good day and walking rapidly back towards the main thoroughfare.

The news broke in the late edition that evening: MICHAEL DALGARNO ARRESTED FOR BRUTAL MURDER OF KATRINA HARCUS IN SECOND TRAGEDY FOR BALTIMORE AND SONS.

Runcorn must think he had enough to go to trial. Please heaven he was right!

But Runcorn was not certain. Monk knew that the moment he spoke to him the next morning, even though he denied it. They were in Runcorn’s office, papers scattered on the desk and the sunlight coming through the window making bright patterns on the rest of the floor.

“Of course it’s enough!” Runcorn repeated. “He was pulling a land fraud against the investors in Baltimore and Sons, and Katrina Harcus knew it. She told him so, begged him to stop. He had two reasons for wanting her dead.” He held up his fingers. “To keep her quiet about the fraud, for which she may well have had proof—and he destroyed it, she as good as told you that. And because he now had a chance of marrying Livia Baltimore, who was shortly going to be a rich woman.” He looked across at Monk challengingly. “And whether he had anything to do with Nolan Baltimore’s death or not, we’ll probably never know, but it’s possible.” He drew in his breath. He held up a third finger. “Added to that, he can’t prove where he was at the time of her death. He says he was at home, but there’s no one who can swear to it.”