When he left, she went through a process she’d been following recently. She searched the house systematically from top to bottom. Every cupboard, every curtain, behind every door. She couldn’t rest until it was done. When she’d arrived in Rundall she’d left doors unlocked, windows thrown open. Things were different now. The more she thought about the disk she’d found on her desk, the more she concluded that one of only five people could possibly have had the opportunity to put it there. There was a spare set of keys to her cottage and to the Taylors’ house kept in a drawer in Rose Guilfoyle’s desk. She knew this because the day after she’d arrived she’d locked herself out and Rose had shown her where the spares were kept. The only people who’d have access to that drawer were Rose, Simon and Cordelia Guilfoyle, and Iain and Marguerite Taylor. Any one of them could have taken the key, let themselves into her cottage while she was at work, put the disk with the others, and left without being seen. It was a horrible feeling, not knowing who you could trust; who might, at their leisure, be going through your things. She had felt she could trust Simon, but perhaps she was wrong. She trusted Oates - except that recently he seemed sometimes to lose track and go off into an unreachable world of his own, unnerving her. Richard she trusted, but his feelings for Cordelia were disturbing. Lilian was okay, but Lilian talked at you - you didn’t feel you could confide in her, or even finish a sentence.
The knowledge that someone could get into the cottage at any time scared her. She’d started doing something else; before she went out, she’d tape a piece of black cotton thread across the lower part of both front and back doors. When she came back she wouldn’t go upstairs until she’d checked to see that both threads were intact. She was becoming obsessive, neurotic. She could see it happening, and it frightened her.
You can read chapter 11 of my lady's gripping thriller here.
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