‘Just a gut feeling at the moment. If I’m right, there are only two ways our suspects could know she was a witness – one, the getaway driver saw her looking at him, or two, someone told them.’

Paul tilted his head and raised his eyebrows.

‘Are you implying you’ve got a leak on the squad?’

Jane sighed. ‘I don’t know, Paul, but there are one or two things that don’t add up. Then again, I could be jumping to conclusions and seeing things that aren’t there.’

‘That sounds familiar,’ he remarked with a grin. ‘You’ve already observed that there’s no sign of any struggle or assault in the bar or hallway area leading to the cellar. It’s the same down here, and there are no broken bottles, which means she wasn’t carrying anything up or down the stairs at the time. There are quite a few footprints, but they could be from any number of people who’ve been down here recently. From the blood pooling and position of her body, I’d say she fell backwards and smashed her skull on the ground.’

‘Do you think she could have been pushed?’

‘I can’t say. There’s no bruising on her face or lower arms to suggest she was punched or grabbed, but the post mortem might reveal bruising on her chest or shoulders, which could be consistent with being pushed.’

Paul went over to the beer barrels and gently lifted each one an inch or two off the ground. He said nothing as he walked upstairs.

‘What are you doing?’ Jane asked, following him.

In the lounge bar he picked up a clean beer glass and handed it to her.

‘Pour me a pint of Heineken, please.’

‘Are you serious?’

‘You should know by now there’s always a method in my madness.’

She held the glass under the spout and pulled the tap forward. At first there was the sound of air, then a few small foamy splutters of beer coughed their way out of the spout, followed by a large sputter, which hit the beer already in the glass. It splashed back up and almost over Jane.

Paul smiled. ‘As I thought . . . The Heineken barrel in the cellar is a fresh one and hasn’t been run through the pipes to ensure an uninterrupted flow of lager from the keg to the glass.’

‘What the hell do you two think you’re doing?’ Murphy shouted.

An embarrassed Jane quickly put the glass on the counter, wishing the ground would open and swallow her up. But Paul knew Murphy of old.

‘Good morning, sir. I’m demonstrating to Sergeant Tennison that Fiona Simpson most likely changed a beer barrel just before her death.’

‘What are you talking about, Lawrence?’

‘It’s not a great revelation, but it could be relevant to her time of death.’