Small and squat with a slightly squashed face, Mr. Cohen has a warm smile and an amiable manner. I thanked him for his work on behalf of Stephen Walmsley.

“That’s our job done then, eh?”

“Yes, as far as the wrongful charge is concerned. What I would like to know is why everything has gone so quiet. I know it will take time to re-investigate and to build a case, but do you have any idea how long, and when there may be other arrests?”

“I’m no more privy to these matters than you are, Mrs. Shackleton. All I can assume is that the evidence isn’t strong enough to bring a case. What you told me about the items in the eaves of the house, that can be explained. The shoes may have been left behind by a guest. Mrs. Brockman’s ownership of a pistol does not make her a murderer, even if the type of bullet matched one found on the shop premises. Pistols are made in vast quantities, more’s the pity. The occupant of a grace and favour cottage—readier to say what she did not see than what she did see—would make a poor witness. Is there anything new that you can tell the police?”

There was nothing new. I clutched at the straw offered by Bernard Campaner of a private prosecution.

Mr. Cohen should have had the grace not to laugh, but his lips formed a pillar box shape and a puh-puh-puh sound came from them as his shoulders moved up and down.

“I am not an expert in French law, but I do know that what they call citation directe wouldn’t be brought in the case of a felony in France, only for a misdemeanour or a petty offence. And they would have more sense than to try such tricks here.”

“What would be needed to take a private prosecution?”

“A dossier would have to go to the Public Prosecutor. There would need to be new and compelling evidence. The chief police officer of every district is bound to give information to the director with respect to indictable offences alleged to have been committed in his district. Your French friends may not even gain entry to the British labyrinth. If they did, a modern-day Charles Dickens could make a novel of it.”

His words hit me like a blow. My arm began to itch intolerably. The bruise on my face throbbed so hard that I wondered if my cheekbone was cracked. Had Campaner known this all along, and simply dangled the prospect of a private prosecution so that I would share information with him? If so, I had been totally naïve.

My time with Mr. Cohen was at an end.

I had a train to catch.