“Happy to help,” she said. “But we’ll have to talk out here. The kids have all got chicken pox.”

Franks passed her the photographs of Mike Withey and Barry Cooper, but Mrs. Stanhope, like everyone else who had bothered to answer their door, didn’t recognize them.

“Have you remembered anything else since you last spoke to the police?” asked PC Daly. It was a routine question.

“Nothing.” Mrs. Stanhope shook her head apologetically. “I mean, when I was at Puddle Ducks—that’s a swimming group for toddlers—we all had a chat about the pest control van parked at Rose Cottage on the night of the fire, but Jean said that wasn’t important enough to bother you with.”

Franks and Daly glanced at each other as the same thought passed through both their minds: why the hell does the general bloody public insist on deciding what’s important and what’s not?

Back in the patrol car, PC Daly held her hands by the air vent to thaw her fingers, while PC Franks got Prescott on the phone.

“It was parked on the grass verge apparently, sir. She saw it on her way to Puddle Ducks at 4 p.m. and it was gone when she drove back home at seven. The fire started at 8 p.m., sir . . .”

Franks held the phone up to Daly’s ear so she could hear Prescott curse and rage.

“She’s so stupid, it’s a miracle she can get herself fucking dressed in the morning!” he ranted.

Daly stifled her laughter as Franks continued, deadpan.

“Pest control vans aren’t uncommon in this part of Aylesbury, sir. Thousands of rats live in the farm buildings and come into the houses for easy food. No, sir, I don’t know why I’m telling you that, sir, no, sorry. Of course she had no right to decide whether it was import—Yes, I’ve got the company name, sir. Daly and I are heading over there now.” Then a longer pause. “It’s a swimming class for toddlers, sir.”

Prescott wasn’t angry with Franks. He didn’t even know Franks. He was angry because now he had to call Ridley and explain how his uniformed officers had not been specific enough—or persistent enough, or experienced enough—to get every little detail out of a bunch of civvies first time round. To calm himself down, Prescott got every spare PC busy watching every second of CCTV from the night of the fire. If the pest control van was parked on the grass verge, it had to have been on the main road at some point.

The pest control van pulled out of the driveway of Rose Cottage and drove away toward the Chiltern Hills. In the driving seat, Angela wore glasses, a wig of cropped brown hair and had a trendy little stubble. Her shoulders were high and tight, brimming with tension. Once the van cleared the more populated areas and headed out into the countryside, she relaxed. Green fields surrounded her, the clear road lay in front of her and there wasn’t another soul for miles around. She peeled the stubble from her chin, pulled her sleeve down over her hand and rubbed her face till it was red—it was so itchy! She then pulled off her wig.