Savage’s flat was in a small, unimpressive block close to the River Kent, which passed through the town. There was a patrol car parked outside when they got there and two officers in high-visibility vests were waiting on the pavement, having been told that detectives were on their way.

The flat was on the second floor and they got no response when they rang the bell so James took the decision to force their way in, instructing one of the officers to get a battering ram from the car. It took just one blow to force the door open.

The interior was small and unkempt, littered with empty crisp packets, beer bottles and overflowing ashtrays. Within seconds they established that the place was empty. There was just one bedroom, a lounge, a separate kitchen and a bathroom.

The bed was unmade and there was unwashed cutlery in the sink. James got the clear impression that the flat hadn’t been occupied for several days and that Savage had left in a hurry.

He noted that Charlotte’s clothes took up most of the space in the wardrobe and drawers, but there were no photos of her or Savage anywhere and not a single Christmas decoration.

They found several pairs of men’s shoes – all a size ten – but none of them showed any obvious signs of blood on the soles, or had a pattern to match the shoeprints left at the farm.

‘It could be he’s still wearing them,’ Abbott suggested.

James agreed and told her to call control and arrange for a forensic team to come to the flat.

As they waited he conducted a quick search, finding a bag full of cannabis capsules and some other pills that looked to be drugs of some kind. But he didn’t come across anything that could be linked directly to the killings at Oaktree Farm. Or anything that told them where Savage was.

There were two other flats on the same floor and by now the police presence had attracted the interest of the occupants. A middle-aged man and a young woman had been asking the uniforms in the hallway what was going on. The man, who said his name was Tom Leyton, lived next door to Savage and one of the officers asked him to tell James what he’d told him.

‘I haven’t seen Neil since Christmas Day,’ Mr Leyton said. ‘I was downstairs when he drove into the car park about lunchtime, and I saw that his car was damaged. I asked him about it and he said he’d been involved in a collision but he wasn’t hurt.’

‘So where did he go then?’ James asked.