‘So table three cases would be the priority, then,’ Levy said in frustrated agreement.

She considered the piles of paperwork in front of her. Sifting cases for prioritisation in this way was far from a perfect system. Ideally she wanted to go through all of them. But with an underfunded thirty-officer squad and a second serious murder to investigate alongside Longman’s, she really didn’t have the resources. Still, she knew where the blame would fall if the murderer did turn out to be on tables one or two. And so at the very least she wanted to review their filtering system; to check that the cases in those piles definitely deserved to be there.

‘OK, I agree with the approach,’ she announced. ‘It’s the best we can do with what we have. Before we start, though, I want to give the filter a test run. Make sure files are in the right categories. Everyone grab a file at random, three from table one and three from table two.’

She waited while all six officers did as instructed.

‘Tucker, who do you have?’

Pat Tucker opened the file he had taken from table one. At the front was a short set of notes. Not his handwriting. One of the others had reviewed the file. Tucker read the notes aloud.

‘Arthur Hart. Single count of murder. Domestic. Killed his wife when she threatened to leave him. Disposed of her body by dismemberment. The offence happened at the end of a long period of stress, both professional and personal. He was released two years ago after eighteen years in prison. Fifty-one years old when convicted. No history of violence prior. Positive progress in prison. Assessed as probably too old to have killed the victim the way Longman died. More importantly, he has shown no propensity for violence of any sort outside of his one offence.’

‘What was Longman’s involvement in the case?’ asked Hale.

‘Longman chaired the hearing that refused Hart’s appeal against his sentence.’

‘So he wasn’t the trial judge?’

‘No.’

Levy considered the facts. Everything she had heard supported the initial file assessment. Hart was not their man.

‘Agreed,’ Levy finally said. Turned to Pickett. ‘Natasha? What do you have?’

‘This one’s from table one,’ Pickett’s file was one she had assessed herself. ‘But it could also have been on table two.’

‘Tell me.’

‘Karl Hirst. One count of manslaughter. One count of GBH. Two counts of kidnap. One count of blackmail.’

‘Table one?’ Hale was already questioning the process. ‘It hardly sounds like violence was an anomaly with this guy.’

‘Except this violence was all on the same single occasion,’ Pickett explained. ‘Eighteen years ago. Hirst was twenty-eight and had no criminal history at all before his arrest. He kidnapped the two children of a local bank manager and threatened their lives to get access to the vault. The bank manager went to the police. Hirst got wind and carried out the threat. Killed the son, seriously injured the daughter. The prosecution couldn’t prove that the death of the son wasn’t accidental suffocation, so he was convicted of manslaughter rather than murder. Longman was the trial judge. Sentenced him to life with a minimum of fourteen to serve. Hirst was released after fourteen, almost to the day. That was just over three years ago.’