‘Housekeeper’s a cow,’ Emma added for good measure.

‘I’ve got a present for you,’ Kelly said to her. ‘The warrant came through on my phone. It’s yours.’

‘Result,’ Emma said. ‘Ready?’ she asked Dan, who stood up and grabbed his coat. Kelly turned back to the screen and sipped her coffee. It was delicious.

‘Guys, before you go, come and show me the layout,’ Kelly asked. Emma and Dan made their way across to Rob’s desk, leaning over it.

The footage showed Laurie Fell and whoever was filming moved closer, paying particular attention to the low thud of music seemingly coming from one room on the ground floor. The people filming began to giggle, and a figure was seen dancing on the grass in front of the phone. Then it ended.

‘Quiet night, just the two of them talking global warming, then. This won’t look good at all, will it?’ she said. ‘Though it’s not exactly a capacity rave. Play it again.’

Dan and Emma peered over Rob’s shoulder. Dan leant over and paused the film, as the vista appeared at its fullest. He pointed out the back of the house and the wooden storage facility where he’d identified equipment for the helicopter.

‘It’s not a hundred per cent clear if Lord Reilly was there, though,’ Dan said. ‘The housekeeper was giving nothing away.’

‘Why would she feel obliged to hide information like that?’ Kelly asked. ‘It’s too late for the Reilly family anyway. The public have already decided he was there. What I need to establish is if the two pilots were also there. We need to bring the housekeeper in under oath, and formally interview her.’

‘Here’s another one,’ Rob said, clicking some keys on his computer.

They huddled around and watched as a video taken from Snapchat showed two young figures in the grounds of the Laurie Fell, dancing in front of the camera. Teenagers had a handy habit of typing a strapline across everything they posted and this one read: ‘Wasted Sunday night!’ It seemed intentionally vague but it confirmed the location and date.

‘Do we know whose accounts these are being posted from?’ Kelly asked.

‘I’ve got two names.’

‘Locals?’

‘Yup. Teenagers.’

‘Right, pick them up for questioning,’ Kelly said. ‘Anything else?’

‘The girlfriends of the pilots were interviewed earlier today,’ Kate said.

Kelly turned around. Kate was standing behind them, holding several printouts. The inquiry was countrywide, though the investigation was based here in the Lake District.

‘One of the girlfriends lives in Holloway and she’s a student nurse. The other lives in Peckham, she’s a teacher. She was sent some WhatsApp messages by her boyfriend on Sunday night, bragging about where he’d been put up for the night. She didn’t know what it was called but my guess is that it’s some kind of swanky residence here in the Lakes.’