Neither Jessica nor DI Cole said anything, not really knowing what their boss might say next. Farraday was rocking back and forwards in his chair. ‘Right, this is what we’re going to do,’ he said. ‘Daniel, first go see this guy the warden was drinking with last night.’

He was hunting through the Post-it notes again. Jessica had already been given a very brief run-down of the prison officer’s movements the night before. She knew he had been walking home from his local pub after stopping out for a drink with one of his work colleagues. The other warden hadn’t been a suspect because, at the exact time Lee Morgan was being killed, his friend’s car had been pulled over for speeding.

The DCI quickly found the note he was looking for. ‘Just see what he’s got to say and then go see this warden’s wife. Suss her out, that kind of thing. Look around the house, see if there’s any expensive jewellery and all that. Cole, you stay here and start sniffing around their bank records. Dodgy deposits, any hidden accounts, all that. I want this guy nailed as soon as possible so we can lump him in with those three other shites who copped it off McKenna. When that’s all sorted, we’ll get back to connecting him to the victims.’

Jessica wondered what their boss was going to spend the day doing but he didn’t take long to tell them. ‘I’m going to get the media boys round. Get the cameras in, then shove this vigilante killer thing right up their arses.’

It was the first time any of them had used the word ‘vigilante’. In police stations it was almost as dirty a term as ‘serial killer’. Generally they didn’t like to make assumptions and would hold back with such labels until they were sure. Jessica felt uneasy hearing it. That McKenna, or who ever the killer might be, was tracking down criminals was something obvious to them all. The fact it could be deliberate vigilantism was also a thought that had crossed her mind but it was a big leap from thinking it to feeding it to the press.

‘Are you going to tell them about McKenna, Sir?’ she asked.

‘Do I think it’s a good idea to tell them our chief suspect is already in prison? No, Daniel, I don’t. For now, we’ll just get the victims’ names out there and see if anyone can link them together for us. If it brings McKenna into the mix then all the better.’

As uneasy as she felt with the idea, Jessica had to admit it wasn’t a bad one. They had tried their usual searches to try to connect the three victims with little luck. Maybe someone who watched the news or read the papers would know something they didn’t?

Jessica had first gone to visit Lee Morgan’s fellow prison guard, who had been drinking with him in the pub the night before. He had already been visited that morning by officers asking about his movements the night before. He still appeared to be in shock but Jessica had never seen anyone quite so relieved to receive three penalty points on their driving licence. He explained he had only had one drink to make sure he stayed under the drink-drive limit. He was feeling guilty about staying out late, however, and ended up driving at 55 m.p.h. along the 40 m.p.h. main road in a hurry to get home.

At the time, he had been angry and annoyed at being pulled over but when the police officers knocked on the door the next morning with the news of his friend’s death – and questions about his own whereabouts – his annoyance had turned to relief that he had an alibi. With his wife in bed when he arrived home and witnesses in the pub quite happy to say they saw the two men leaving together, he knew he could have been in big trouble if he hadn’t been stopped.

By the time Jessica arrived, that relief had turned back into shock at his friend’s death. He told Jessica he and Lee just made small talk at the pub and that they went out for a quiet drink once a month or so.

‘I don’t think Lee had many friends,’ he said. ‘I always felt sorry for the guy. He was a bit of a moaner but harmless enough.’ Jessica figured they would find out quite how harmless he was in due course. She asked if he had heard any rumours of malpractice around the prison but he insisted he hadn’t.

From there, she drove to Lee Morgan’s house. A family liaison officer was already there to support the man’s widow. Carla Morgan looked a lot older than her husband had done. Jessica now knew Lee had been fifty-six but his wife looked as if she was in her late sixties. The officer let Jessica into the house and showed her into the living room. Carla had been sitting in a comfy-looking recliner but stood gingerly to greet her.

She apologised needlessly for her lack of mobility. ‘Sorry, dear, I had to have my hip replaced six months ago,’ she said.

Jessica said it was not a problem and helped the woman back into her seat. Given the marks around her eyes, it was clear Carla had been crying that morning but she now seemed relatively fine. Farraday’s suggestion to ‘suss’ the woman out seemed ridiculous given the state of her. The other officer went to make some tea, leaving Jessica and Carla alone in the living room.

She asked some relatively harmless questions about how the couple had met and how long they had been together. The information wasn’t essential but Jessica knew she couldn’t dive straight in and ask the woman if she knew whether her husband, who had only been killed the night before, took money on the side or not. She did take those moments to look around the room. Ultimately she knew it was very likely the house would be searched thoroughly by a trained squad in the next day or so anyway – especially if Cole found anything suspicious in the couple’s bank records.

The television certainly looked new, large and flat, pinned to the wall and surrounded by large speakers with other media players and a digital box underneath. Jessica had already noticed the black hatchback car parked on the drive. It had a registration plate from the year before and was sparklingly clean. The whole house was incredibly well kept, not something out of the ordinary in itself but perhaps surprising because of Carla’s clear difficulties in getting around. It was those types of detail Jessica was trained to spot. She knew the couple had no children, so unless Lee Morgan was an avid tidy-upper after a long day at work, then the pair were likely paying a cleaner.

As the other officer returned with some drinks, Jessica asked where the toilet was. Carla gave her the directions and she made her way out into the hallway then went up the stairs, not looking to go snooping but wanting to get a feel of the house. There were no obvious illustrations of wealth but there were framed photographs on the wall the entire way up the staircase. All of the pictures were of the two Morgans and seemed to be from recent years given the similarity in their appearances. Each one was taken in an exotic location with beaches, attractive-looking palm trees or clear blue ocean in the background.

There wasn’t much more for Jessica to see at the top of the stairs but an overall impression was emerging that the couple might not be overtly rich but were certainly comfortable.

Back downstairs, Jessica sat on the sofa close to Carla. The other officer left them alone again. ‘It’s a nice place you have here, Mrs Morgan,’ she said.

The woman nodded. ‘Thank you. Lee was always talking about having somewhere nice to retire to. It’s taken us a while but we’ve got the house the way we wanted.’

‘I liked the photos on the way upstairs . . .’

The woman smiled sadly. ‘Yes. Can you believe I’d never been on a plane until three years ago? Lee had been talking about it for years but we never had the money and I was always a bit scared of flying.’

‘Where did you go?’

‘We went to Egypt first of all. Lee wanted to go to the Caribbean but I didn’t want to go too far. It was nice but a bit too hot. The year after, I let him have his way and we went to Antigua. The island was amazing but I didn’t like being on the plane for so long.’ She motioned towards her back. ‘Last year we just went to France. It was warm but I don’t think Lee really took to the food and neither of us could speak the language so it wasn’t easy.’