The inevitable flurry of work that came with trying to tie up their investigation kept the team at their desks until late. O’Malley and the DCI spent a good hour shut away with DCS Wilkinson, going over and over the upsides and downsides to pursuing a case against Louise Reakes. Lightman spent the time writing up a preliminary report, which would be used to create a press release the next day. Hanson, meanwhile, finished compiling her list of assaults, rapes and murders across Southampton and major cities within a potential day trip or overnight distance, and started comparing Alex’s diary and messages with them.

Gianetta Jilani’s attack was almost definitely a match. The database revealed that the student had originally gone to Rain in Portsmouth. Earlier in the same WhatsApp thread where Alex had posted the photo of the knife, she found that this was the club his group had arranged to meet at.

She’d found other possibilities, too. One of which she didn’t quite want to connect to Alex. A thirty-four-year-old Londoner named Laura Stevenson had last been seen at a bar in Camden Town in May. Her body had been found in the canal four days later. She had been stabbed twice in the back.

She’d had long dark hair, like Louise Reakes. Like Alex’s mother. It was much like all the hair they’d found in that box. And blood tests had showed traces of Viagra in her system.

Alex had, it turned out, been away that night. A lads’ night in London. It matched up too well.

Hanson sent McCullough a summary of the report and asked if she could look at the post mortem. They needed to know whether the weapon that had killed Laura Stevenson might have been the same as the knife that had killed Alex. The next step would be to DNA test the hair strands in the box and compare them with any DNA of the victims of attacks.

Their theory on the knife was that Alex had ordered a second one to a different address. They were confident they would connect him to another order in the end, even if it meant going to the original makers of the knife in Poland and checking up with them.

At nine fifteen the DCI announced that he’d spoken to the Crown Prosecution Service. The CPS were not enthusiastic about charging Louise Reakes with either the more severe charge of murder or the lesser charge of manslaughter. There was an ongoing debate about whether the perversion of justice charge should go ahead, but they had two more days in which to make a decision.

‘I know what she did was pretty sneaky,’ Hanson told them all, ‘but I hope they let it lie.’

‘I hope you aren’t expressing a personal opinion that isn’t in line with the letter of the law,’ O’Malley said, giving her a grin.