When Kelly went to leave the house the next morning, she didn’t disturb Ted. She’d got in late. But she was glad she’d taken the time out to meet him and Johnny. The spare room door was shut tight and she crept downstairs, made a coffee and checked her emails. The fire department had got back to her and she flicked through the report. It was detailed and lengthy – as she’d expected – and she closed it to read in more detail later. The post dropped through her door and she went to pick it off the mat.

The sun shone through the windows and lit up her hallway all the way from the back, where it overlooked the river, to the front. She lived in a quiet part of Pooley Bridge, away from the tiny central square where all the tourist shops and cafés plied their trade. The odd ice cream seller parked up outside her house in summer, because it was along the route to the steamer that took day trippers to Glenridding and Howtown.

She bent to pick up the post and flicked through it, stopping at a handwritten letter with a Surrey postcode. She recognised the writing. She sighed and lowered the envelope, tempted to throw it straight into the waste bin. She looked at the letter and couldn’t help but be a little intrigued by what might be inside. The mind of a psychopath was something that the most eminent psychologists all over the world would give their life savings to unpick, and here she was, being contacted by one of the sickest. After the Amy Richmond case, she’d had letters, emails and phone calls from professors from Beijing to Canada asking for her opinion on what motivated the series of gruesome killings that gripped the Lake District.

She’d ignored them all. She couldn’t begin to explain what she thought motivated such cold and calculated actions. It was all she could do to manage the grief of the families and stretch resources so that they had enough liaison officers attending them. The money didn’t last forever, and at some point, the support was withdrawn. But crimes such as those perpetrated by The Teacher never went away. They weren’t just murders; they were lessons. Amy had played God for a while and got away with it.

She threw the letter into her bag and packed the rest of the stuff she’d need for the day: her water bottle, her running kit – just in case she got the chance – and a few packs of food she’d prepared to eat at her desk. On her way out, she grabbed an apple.