'I'll pass on that information,' said Leeming. 'I'm sorry to have disturbed you, sir, but I didn't only come to tell you what happened to Mr Kellow. There's another troubling matter.'

'My assistant is murdered and a silver coffee pot is stolen – what can be more troubling than that?'

'We believe that Mr Kellow may have had keys to the shop.'

'He did,' confirmed Voke. 'He had to let himself in.'

'Those keys have vanished. Inspector Colbeck, who is leading the investigation, sent me specifically to give you a warning. Look to your property, sir. It may be in danger.'

Robert Colbeck and Jeremiah Stockdale ended the day in the lounge of the Railway Hotel with a glass of malt whisky apiece. Before they compared notes about what they had learnt, Stockdale banged the arm of his chair with a fist and made his declaration.

'I want this man caught and caught quickly, Inspector,' he said. 'I won't tolerate murder in my town. I police Cardiff with a firm hand and villains fear me for that reason.'

'Your reputation is well-earned, Superintendent, but why do you think the killer must be a man?'

'It's what you suggested. You felt that a woman was involved to lure Mr Kellow here but that she needed a male accomplice to do the deed itself. How else could it have happened?'

'I've been mulling that over. The young woman could have been acting alone.'

Stockdale shook his head. 'No, I refuse to believe that.'

'Look at the way he was killed,' said Colbeck. 'He was struck on the head to daze him then acid was poured down his throat. Why choose that method? Remember that Mr Kellow was defenceless. A man would either have strangled him or battered him to death. A woman, on the other hand, would be less likely to turn to violence.'

'She could have stabbed him.'

'Most women would draw back from that. No, I think that she deliberately selected acid and I'll be interested to find out why. In doing so, of course, she does give us a definite line of enquiry.'