‘So he’s corrupted her,’ said Leeming with disapproval.

‘Oh, I suspect that she was not entirely without corruption beforehand, Victor. How else could she meet him in the first place without frequenting the sorts of places he tends to visit? All that he did was to draw her deeper into the criminal fraternity.’

‘Where could she have got hold of a gun?’

‘She and Oxley would travel with a weapon all the time.’

‘He was carrying a pistol when we arrested him,’ noted Riggs.

‘Then his accomplice could have bought a second one. It’s not difficult if you have enough money, and they’d just committed a robbery in Birmingham, remember. No,’ Colbeck went on, ‘I don’t think we should waste time speculating on how she acquired the weapon. The first thing we must do is to unmask the second accomplice.’

Riggs blinked. ‘There were two of them?’

‘Yes, Sergeant, and I’m afraid to tell you that one of them wears a police uniform. Oxley’s mistress had help from one of your men.’

‘That’s a disgraceful allegation!’ shouted Riggs, banging his desk. ‘I can vouch for every one of my constables. None of them would dream of being party to a plot to murder two of their fellow officers.’

‘I’m sure that’s true,’ said Colbeck, ‘but, then, the man I’m after would have had no idea that such dread consequences would ensue. It probably never occurred to him that he was aiding and abetting the escape of a desperate criminal.’

Riggs folded his arms. ‘Explain yourself, Inspector.’

‘Very few people must have known when Oxley was being transferred from here to Birmingham. Is that agreed?’

‘Yes — only a handful of us had the details.’

‘I need the name of every man who knew the exact train on which the prisoner would be taken this morning. You, presumably, are one of them.’