It left Bagley with the impression of two tough and determined women who, for different reasons, had wanted MacKenzie dead. An impression not helped by the various weapons hidden around the house, particularly Jess’s baseball bats and my carving knives. To Peter’s credit, he tried to set the record straight as soon as he realized the damage he’d done, but by then it was too late. If both Ms. Burns and Ms. Derbyshire were subject to panic attacks and agoraphobia, Bagley asked, why had we shown no evidence of it that night?

“You watched,” he echoed now. “Yet I understand Dr. Coleman asked you to call the police and an ambulance. Why didn’t you do that?”

“The landline wasn’t working.”

“But you knew your mobile worked in the attic.”

“I didn’t think it was a good idea to leave Peter alone with MacKenzie.” I rested my forehead on my hands and stared at the table. “Look, what I’m going to say isn’t very kind, but it is true. Peter was petrified from beginning to end of the whole thing. I didn’t blame him-I don’t blame him now-but I guarantee MacKenzie would have freed himself somehow if I hadn’t stayed.”

“How?”

I dropped my hands into my lap. “Probably by pretending to be more injured than he was. Peter was uncomfortable about the way I’d bound his hands behind his back, particularly when he realized the fingers were broken. He wanted me to retie them at the front while MacKenzie was still unconscious.”

“But you refused. Why?”

“Because I wasn’t as convinced as Peter that he was unconscious.”

“You think a doctor would make a mistake about something like that?”

I shrugged. “It’s hardly difficult to fake but, in any case, it wasn’t a risk worth taking. I couldn’t see Peter leaping to my rescue if MacKenzie decided to grab me round the throat and throttle me. There’d have been a lot of hand-flapping and not much action. He made a hell of a fuss about getting Bertie’s blood on his trousers.”

It wasn’t a very fair description of Peter but it seemed to strike a chord with the Inspector. “Dr. Coleman certainly seems to have found the experience more”-he searched for the appropriate phrase-“soul-destroying than you and Ms. Derbyshire.”

“You don’t know much about women then,” I said flatly. “If it’ll bring an end to this, I’ll happily burst into tears and throw hysterics. Is that what you want me to do? It’s easily done…almost as easy as MacKenzie pretending to be unconscious.”

A gleam of humour appeared in his eyes. “I’d rather you told me why you persuaded Dr. Coleman to go back to his own house and call the emergency services from there. That puzzles me.”

“It didn’t happen like that,” I demurred. “It was Peter’s idea…I merely agreed it was sensible.”

The Inspector consulted his notes. “Dr. Coleman has the roles reversed, Ms. Burns. I quote: ‘When I told Connie we needed the police and an ambulance as a matter of priority, she pointed out that MacKenzie had cut the telephone line. She said the only option was for me to go home and call from there. I agreed.’ ”

“I honestly don’t recall it that way…but does it matter?”

He frowned. “Of course it matters. There were five working mobiles in the house, yours, Dr. Coleman’s and Ms. Derbyshire’s…plus Mr. MacKenzie’s and your father’s. We’ve already established there’s a perfectly good signal in the attic, so why not send Dr. Coleman upstairs? Why tell him going home was the only option?”

I shook my head. “I don’t remember doing that…but, even if I did, how does it make me the bad guy? Peter knew about the signal in the attic. He could have thought it through just as well as I could. It wasn’t a normal situation…we weren’t exactly sitting around, discussing the best way to proceed, you know. We were both shaking like leaves…and all I recall is jumping at the first suggestion that was going to bring us some help.”

“In fact Dr. Coleman expressed surprise when we told him it was possible to use a mobile at Barton House.”

“Then he’s two-faced,” I said crossly. “He knew all about the pyramid Jess built in the back bedroom so that I could use my laptop when I first arrived. You can ask my landlady. It was Peter who told her about it when I asked permission to install broadband.”

The Inspector steepled his hands in front of his mouth and studied me reflectively for several seconds. “He recalls that now,” he agreed, “but not at the time. And you didn’t remind him.”

“Then I can only apologize for a blonde moment,” I said sarcastically. “Has Peter apologized for a senior moment? It all happened very fast. As soon as he made up his mind to go, he ran for the door.” I folded my hands on the table. “I wish I could make you understand how disorientated we all were…but maybe you’ve never had a psychopath break into your house and take you prisoner.”

He didn’t rise to that bait either. “So what happened next? When did Ms. Derbyshire join you in the hall?”

“Almost immediately. She heard Peter’s car on the gravel and came down to find out what was happening.”

“Were the dogs with her?”

“No. She left them in the bedroom…she was worried they’d start sniffing around Bertie.”

“What was she wearing?”

“My dressing-gown. It was too long for her and trailed across the floor. She knelt down to stroke the dog, and-” I sighed. “It all got very messy.”

“What was on her feet?”

“Nothing. None of my shoes fit her. Which is why she asked me to find her boots.”

“But you weren’t wearing shoes either.”

“No, I took them off before I went into the hall. I didn’t want MacKenzie to hear me coming.”

Bagley nodded. “What made you look for Ms. Derbyshire’s clothes outside the office window?”

“Because they weren’t in the office. MacKenzie had kept her knickers-he’d put them in the bag-but there was no sign of anything else. Then Jess told me she’d heard the window open and close after he put her on the footstool…so I raised the sash and spotted them immediately.”

“And you went through the kitchen to retrieve them?”

“You know I did. You found my bloody footprints.”

“Mmm. And during the time it took for you to go outside and return, Ms. Derbyshire was alone with Mr. MacKenzie?”

“Yes,” I said wearily. “We’ve been over this twice already. I ran-you can measure my strides-and when I returned, the only thing that was different was that Jess was sitting in the armchair under the stairs. If you spray it with Luminol I’m sure you’ll get a reaction from the bloodstains on my dressing-gown.”

“You’re very knowledgable about crime scenes, Ms. Burns.”

“I’ve covered a fair number of trials over the years. It’s amazing how much information you pick up from hours of police evidence. You should try it yourself some time.”

It was impossible to provoke him to anything other than displays of polite scepticism, except when it came to MacKenzie’s disappearance. On that subject, his disbelief was total. Yet again, he took me through the sequence of events.

“You say MacKenzie was lying on his side and you could see the duct tape was still firmly in place.”

“Yes.”

“You then handed Ms. Derbyshire her clothes and suggested she have a bath to wash off Bertie’s blood because it was clearly distressing her. She went directly upstairs, and shortly afterwards you heard the water running.”

“Right.”

“You were also distressed by the dog’s blood, so you chose to wash in the kitchen sink before changing into a skirt and T-shirt that were waiting to be ironed in the scullery. And to avoid the blood setting on your stained clothes, you left them soaking in a bleach solution in the sink…because they were ‘whiteish’ and made out of cotton.”

“Yes.”

“Did you expect it to work?”

“Not really, but it seemed worth a try. My wardrobe’s hardly bursting, and it was only dog’s blood. The pathologists will prove me right. I’m sure I’ve read somewhere that DNA is still recoverable after a garment’s been washed.”