Pip un-paused it and watched as Jamie walked quickly down the hallway, ignoring all the commotion in the dining room, eyes down on his phone. Cara’s head is turned, following his progress for half a second, before the ball lands in the cup and the screaming pulls her attention back into the room.

Four seconds.

The sighting lasts just four seconds. Then Jamie is gone, his white trainer the very last trace of him.

‘Found him,’ Pip said.

Thirteen

Pip dragged the cursor back and pressed play to show Ravi.

‘That’s him,’ he confirmed, resting his sharp chin on her shoulder. ‘That’s when Cara saw him. Look.’

‘Who needs CCTV when you have Snapchat stories,’ Pip remarked. ‘Do you think he’s walking down the corridor towards the front door?’ She turned to watch Ravi’s eyes as she played the clip again. ‘Or further into the back of the house?’

‘Could be either,’ Ravi said. ‘Hard to tell without knowing the layout of the house. Do you think we can go round to Stephen’s and see?’

‘Doubt he’ll let us in,’ she said. ‘He doesn’t want his mum to know about the party.’

‘Hm,’ said Ravi, ‘we might be able to find the floorplan on Zoopla or Rightmove or something.’

The video kept playing beyond the beer pong, into another clip where Peter was hugging the toilet, throwing up into it while Chris giggled behind the camera, saying: ‘You alright, big man?’

Pip paused it so they didn’t have to listen to any more of Peter’s retching.

‘Do you have a time for that Jamie sighting?’ Ravi asked.

‘No. Chris just sent me the saved story; it doesn’t have time-stamps for any individual part.’

‘Call him and ask him.’ Ravi reached across, dragging her laptop towards him. ‘I’ll see if I can find the house on Zoopla. What number is Stephen?’

‘Nineteen, Highmoor,’ Pip said, spinning her stool to face away from Ravi and taking out her phone. She had Chris’ number in here somewhere. She knew she did, because they’d done a group project together a few months ago. Aha, there it was: Chris M.

‘Hello?’ Chris said when he picked up. The word trailed up like a question; clearly he hadn’t saved her number.

‘Hi, Chris. It’s Pip.’

‘Oh, hey,’ he said. ‘I just sent you an email –’

‘Yeah, thank you for that. That’s actually what I wanted to ask you about. This clip here, of Peter playing beer pong, do you know what time it was taken?’

‘Um, can’t remember.’ Chris yawned on the other end of the line. ‘I was quite drunk. But, actually, hold on . . .’ His voice grew echoey and distant as he put her on speaker. ‘I saved that story so I could abuse Peter with it, but I take videos in the actual camera app because Snapchat always crashes on me.’

‘Oh, that’s great if it’s on your camera roll,’ Pip said. ‘It’ll have a time-stamp.’

‘Crap,’ Chris hissed. ‘I must have deleted them all, sorry.’

Pip’s stomach dropped. But only for a second, crawling its way back up as she said: ‘Recently deleted folder?’

‘Oh, good shout.’ Pip could hear the fiddling of Chris’ fingers against the device. ‘Yeah, here it is. Beer pong video was taken at 9:56 p.m.’

‘9:56,’ Pip repeated, writing the time down in the notebook Ravi had just slid across to her. ‘Perfect, thank you so much, Chris.’

Pip hung up the phone, even though Chris was still speaking. She’d never been a fan of those straggling bits of talk that happened at the beginnings and ends of conversations, and she didn’t have time to pretend right now. Ravi often referred to her as his little bulldozer.

‘Hear that?’ she asked him.

He nodded. ‘And I’ve found the old listing of Stephen’s house on Rightmove, last sold in 2013. Photos don’t give much away, but the floorplan is still up.’ He turned the screen back, showing her a black and white diagram of the ground floor of Stephen’s house.

Pip reached for the screen, tracing her finger from the 16’ by 12’5” box labelled Dining Room, out of the double bi-fold doors, turning left down the corridor to follow Jamie’s path. That way led to the front door.

‘Yes,’ she hissed. ‘He was definitely leaving the house at 9:56.’ Pip copied the floorplan and pasted it into Paint to annotate it. She drew an arrow down the corridor towards the front door and labelled it: Jamie leaves 9:56 p.m. ‘And he’s looking at his phone,’ Pip said. ‘Do you think he’s about to call whoever George then sees him on the phone with?’

‘Seems likely,’ Ravi said. ‘That would make it a pretty long phone call. Like, half an hour at least.’

Pip drew a pair of forward and backward arrows, outside the front door on the floorplan, as Jamie had paced the pavement on his phone. She labelled the timespan of the phone call and then drew another arrow leading away from the house, when Jamie finally left.

‘Have you ever considered becoming a professional artist?’ Ravi said, looking over her shoulder.

‘Oh, be quiet, it does the job,’ she said, poking the cleft in his chin. Ravi uttered a robotic ‘Booooop,’ pretending to reset his face.

Pip ignored him. ‘Actually, this might help with that other Jamie sighting.’ She pulled up the photo of Jamie standing behind Jasveen and her stained top. She dragged it to the side to split-screen it beside the floorplan. ‘There’s a sofa there, so this has to be the living room, right?’

Ravi agreed. ‘Sofa and a bay window.’

‘OK,’ Pip said. ‘And Jamie’s standing just to the right of that window.’ She pointed to the bay window symbol in the floorplan. ‘But if you look at his eyes, he’s looking away, to the left.’

‘Can solve murders, but can’t tell her left from right,’ Ravi smiled.

‘That’s left,’ she insisted, glowering up at him. ‘Our left, his right.’

‘OK, please don’t hurt me.’ He held his hands up in surrender, his crooked smile stretching across his cheeks. Why did he enjoy winding her up so much? And why did she like it when he did? It was maddening.

Pip turned back, placing her finger on the floorplan where Jamie had been standing, and drew her finger out, following Jamie’s approximate eyeline. It brought her to a boxy black figure against the next wall. ‘What does that symbol mean?’ she asked.

‘That’s a fireplace,’ said Ravi. ‘So Jamie was watching someone who’s standing near that fireplace at 9:38 p.m. Likely the same someone he followed from the memorial.’

Pip nodded, marking these new points and times on the annotated floorplan.

‘So, if I stop looking for Jamie,’ she said, ‘and instead look for photos taken near the fireplace around 9:38, I might be able to narrow down who that someone is.’

‘Good plan, Sarge.’

‘You get back to your job,’ she said, pushing Ravi away with her foot, back around the island. He went, but not before stealing her sock.

Pip heard just one click of his mousepad before he said, quietly, ‘Shit.’