I turn back to the map and then the timeline. `OK, let's start with what we know. The bus arrived at 9.43, Patsie, Isabel and Sasha got on and Leah started to walk home.'
She nods. `Which is supported both by Isabel's bus ticket and what we got from Leah's mother.'
`Right. But we only have that one ticket, don't we? What if Isabel got on that bus alone? What if Patsie went off with Sasha much earlier than that `“ even as early as 9.00 `“ and Leah and Isabel then hung around on their own for half an hour or so before going home?'
Gallagher's eyes widen. `You mean they did it deliberately? To create a fake timeline?' She gives a low whistle. `You're talking about a pretty sick conspiracy there, DI Fawley. But OK, let's play it through. Have we ever nailed down where they went after they left the pizza place?'
`They claimed they just `њhung out`ќ. You know `“ on those benches up by South Parade. Which are conveniently out of range of any CCTV.'
Gallagher nods. She knows the place, of course she does `“ she lives up that way herself. And there are always kids mooching about there in the evenings. Smoking, drinking cider. `Hanging out.'
I take a step closer to the board; my head is buzzing. `What if this whole thing is a lie? What if Patsie and Sasha started for home straight after leaving the restaurant? Only they didn't get a bus. They walked.' I trace the route `“ down the Banbury Road and then along the Marston Ferry Road towards Cherwell Drive. And then I stop and tap the map.
`Here,' I say, turning to her. `This is where they stopped. This is where they turned off.'
The footpath leading to the Vicky Arms. Barely a hundred yards from where Sasha's body was found.
Gallagher considers. `It would have been pretty dark along there at that time of night.'
`Patsie could easily have brought a torch. If it really was that premeditated.'
Gallagher glances at me. `But why would Sasha go with her?'
I shrug. `She didn't know Patsie intended her any harm, did she? They were supposed to be best friends `“ they'd known each other since playschool. Perhaps Patsie said she wanted to go to the pub. Perhaps they were supposed to meet some boys. Who knows.'
`OK,' she says. `Then what?'
`As soon as they're out of sight of the road, Patsie turns on Sasha and kills her, then drags the body into the river `“'
`Sasha's phone,' says Gallagher suddenly. `The last signal was at 9.35. We thought her battery had run out, but perhaps it wasn't that at all. Perhaps the phone went dead then because Patsie had just chucked it in the Cherwell.'
It fits; it all fits.
Gallagher moves closer to the map. `And after that Patsie just heads off home on foot as if nothing had happened?'
I nod. `And when she gets there, she makes a big point of talking to someone in the street, so they'll remember seeing her. Meanwhile Isabel gets on the 9.43 bus in Summertown, making sure to ask the driver the time when they're approaching Headington.'
`Perfect little alibis, gift-wrapped and ready to go,' says Gallagher. `All they have to do after that is keep on insisting all three of them were on that same bus.'
I sense someone come up behind me now and turn to see Gislingham at my shoulder.
`Good news,' he says. `Someone called in `“ looks like we've found Sasha's handbag. It was up near the Vicky Arms. Quinn's on his way to the lab to take a look.'
I stare at him. `Where was it `“ where exactly?'
He goes up to the map and points. `About there, I think `“ in a ditch on the corner of Mill Lane.'
Halfway between where Sasha died and Patsie lives. This isn't just a hunch any more. This is evidence; this is a case. And for the first time since this all began, I'm staring at the photos of Sasha with a picture in my head of who did that to her. The body head-down in the water, the bound wrists, the jagged lacerations. The white and broken face.
`Something else occurred to me as well, boss,' says Gislingham quietly. `What you were saying about Patsie Webb `“ no one saw anything on her clothes when she got home, did they? Perhaps that's why she used that plastic bag. Something to keep her clothes clean and tidy while she beat poor bloody Sasha's head in.'
Gallagher looks across at him. `I suspect you're right, Sergeant. But I don't think that was the only reason. She didn't want to look at her. She couldn't bear to see her face.'
* * *
Interview with Patsie Webb, conducted at St Aldate's Police Station, Oxford
9 April 2018, 6.45 p.m.
In attendance, DC V. Everett, DC E. Somer, Mrs D. Webb, J. Beck (solicitor)
ES: Interview resumed at 18.45. Patsie has been given time to consult with a lawyer, and Mr Jason Beck is now present.DW: I can't believe you arrested her `“ you can't seriously think `“ES: We don't `think' anything, Mrs Webb. We just want the truth. Which is why I'd like Patsie to tell us what happened that night one more time.PW: What again?ES: Yes, again. You say you left Leah in Summertown at about 9.45, when the three of you got on the bus.PW: I told you that `“ Iz gave you her bloody ticket, didn't she?ES: Yes, that's right, she did.VE: And then you got off on the Marston Ferry Road, and Sasha stayed on till Cherwell Drive, and the last time Isabel saw her she was standing at the bus stop, waiting for someone?PW: Right.VE: And Isabel stayed on the bus till Headington.PW: Right.VE: And she spoke to the bus driver. To ask him the time.ES: You see, that's always struck me as odd. I mean, that she spoke to him at all.PW: Don't see why.ES: Young people like you `“ you don't bother with watches any more. You check the time on your phones. Why did she need to ask the driver?PW: Dunno. Perhaps her phone was off.VE: Good guess. You're right, it was. We checked. In fact, we've now established that all your phones were off between 9.00 and just after 10.30. Yours and Leah's and Isabel's. And that's odd too.PW: [shrugs]ES: So we started asking ourselves why. Could it be, perhaps, that Isabel wanted an excuse to talk to that bus driver `“ that she wanted him to remember her? After all, she looks pretty distinctive, doesn't she, with that bright-pink dip-dye of hers? He wasn't likely to forget that.VE: When did she dye it, Patsie?PW: [shrugs]
Can't remember.VE: It must have been pretty recent because she didn't have it when she met her mother on Walton Street.PW: Whatever.ES: And that was just a coincidence, was it? That she happened to dye it just before what happened to your friend?PW: I don't know what you're getting at. Look `“ what difference does it make? We were on that bus, you know that. Iz gave you her ticket.ES: Precisely. We know Isabel was on the bus. There's proof of that. But what about you, Patsie? Where's your ticket? Or don't you have one?* * *
`What have we got?' asks Quinn.
The contents of the evidence bag are spread out on the lab table. A satchel. Soft leather, deep pink, with dark discoloured patches where it's been out in the open and the wet for days. A pen with a bedraggled feather attached to the end. A purse. A make-up bag. A tampon wrapped in orange plastic. A packet of mints.
`It's definitely Sasha's bag,' says Nina Mukerjee, opening the purse and taking out a series of plastic identity cards. She's wearing thick latex gloves. `These are all hers.'
Most people use the same passport picture for everything, but not Sasha. A slightly different her stares out from each card. More and less of a smile, more and less of a playfulness.