Hitchens pinned more photographs on the board. From the location of the bullet near the spine, ripples had spread out like a stone dropped in a pond, tearing flesh and crushing soft tissue. The body was almost all water, after all – and the energy of a bullet’s impact was converted into hydrostatic force, equivalent to the devastation of a tsunami.

‘So far, we can’t put anyone else at the scene,’ said the DI. ‘In fact, we don’t even have anyone to perform an official identification until her GP returns. According to the post-mortem report, the victim was medically incapable of conceiving, so there are no children in the picture. Right now, the nearest thing to a next of kin is her part-time handyman.’

After the briefing, Fry went with Hitchens to the DCI’s office to report her progress on the Darwin Street fire enquiry.

‘When he’s well enough, I want to take the husband back to the scene,’ she said, after she’d finished bringing her senior officers up to speed. ‘Today, if possible. As soon as he’s discharged from hospital.’

‘Why?’

‘For a start, I want to see how he reacts. His response to the deaths of his wife and children has been a bit difficult to judge so far, but that could be the sedatives they’re giving him at the hospital. Also, I haven’t told him any details of how the fire started. I’d like to see if he’s drawn to the seat of the fire, or if he lets slip something that he shouldn’t know. Alternatively, if he’s innocent, he might be able to point us to some item that doesn’t belong in the house, which might indicate an intruder or a visitor that we don’t know about.’

‘So you fancy the husband for this one, Diane?’

‘Yes, sir. The neighbours say there had been problems in the marriage. Mr Mullen even moved out for a while, though it’s not known where he went. And his alibi for the time the fire started is a bit suspect – it relies entirely on his best friend, a man by the name of Jed Skinner. I think I might be able to break that alibi down without too much trouble. But I need to do it before Mr Mullen is discharged from hospital, so they can’t get together and tighten up their story.’

Kessen looked at her report. ‘If Mr Mullen is telling the truth, there must be at least one other person who can substantiate his alibi – the taxi driver who brought him home.’