He left, and Hanna snapped a switch. ‘No one is to come into my office unless I say so. I repeat, no one at all. If anyone wants me, tell me.’ He switched off the intercom, leaned back in his chair, and said, ‘Sit down, Mr Kemp.’

I took the chair on the other side of his desk and studied him. He appeared to be screwed up to a pitch of tautness I had not seen before. His eyes were exceptionally bright and his movements precise and controlled to the point of being finicky. He said, ‘It is now more essential than ever that you stay out of the hands of the police, especially the uniformed branch. I would hate to lose you – or Miss Tomsson – at this stage.’

I stretched out my legs and smiled at him. ‘I’m right in the middle of police headquarters. A funny place to be.’

‘The police are hardly likely to look for you here,’ he said casually, and took a file from a drawer. ‘Let me explain the importance of all this.’ He opened the file. ‘The men who attacked you – Sergeant Taylor and Constables Whitley, Villegas and Robertson – dropped out of sight. When Commissioner Barstow countermanded my orders and took them from here, those four officers neither reported to their posts in Hogtown nor did they go to their homes. What do you make of that?’

‘I’d say Barstow is covering something up.’

Hanna nodded. ‘I’ve had the forensic laboratory working around the clock. I took it on myself to have the homes of all four men raided and their civilian clothing impounded for examination. On the clothing of Taylor and Villegas we found blood specks of the same blood group as Ogilvie. On one of Robertson’s boots we found a thread caught up in a projecting nail. The thread is of the same material as Ogilvie’s trousers and is not of a type usually found in Campanilla. Nothing was found to implicate Whitley in Ogilvie’s murder, but we’re still looking.’

I took a deep breath. ‘That’s a damn fine bit of work.’

‘Normal police procedure,’ said Hanna impassively. He put his hands on the desk and leaned forward. ‘Mr Kemp, I must emphasise that as far as you are concerned, the position has changed. There is a lot going on in the uniformed branch of the police force that I don’t like and I am afraid for your safety, and for that of Miss Tomsson. The fact is that a man cannot be convicted on a blood group specimen and Mr Ogilvie’s blood grouping was not uncommon. So we’re not going to be able to charge them with that – yet. But you and Miss Tomsson can give evidence against Taylor and his men on the matter of the direct assault on you. And that is why you must stay out of sight until I clear up this matter.’