It wasn’t as if she was coming up with anything that pointed the finger of suspicion at anyone she knew about. Heart of Glass was the terrifying story of two serial killers, one deliberate, the other accidental. The central character was a mystery novelist who realized that every time he created a particular murderous scenario, it was reflected almost immediately in real life. As an experiment, he deliberately wrote a book where his despised older brother, thinly disguised, died in a murder made to look like a freak accident with an exploding beer bottle. Just as Penny herself had died. Within weeks, his brother was dead, by almost identical means.

With this gruesome proof of his gift, the writer set about killing off everyone he had ever disliked. Judging from Penny’s novel, he’d devoted a lot of energy over the years to hatred. In parallel with his remote-controlled homicidal spree ran the story of a surgeon who had developed his surgical skills in the bedrooms of his victims as efficiently as he had in the operating theater. He had been killing successfully for years, escaping detection by never murdering in the same city twice. An international serial killer, he’d earned frequent flyer miles for murder.

The connection between the two men was the surgeon’s wife, who was also the writer’s editor. The final ingredient in the heady stew was the wife’s lover, a charismatic congressman about to mount a presidential campaign.

Knowing that Penny used elements of her friends, acquaintances and professional contacts in the construction of her characters, Lindsay tried to match the characters in the book to people she knew in Penny’s life, to see if any clues lay there. But Penny was too skilled in her craft to have left an obvious trail leading back to her immediate circle. Even where parallels seemed possible, there were no correlations that struck Lindsay. The editor was nothing like Baz, being a weak character swept along by events, unable to control her life. Nothing like the woman Meredith had described, a woman capable of seizing the opportunity for infidelity, then taking steps to make certain it didn’t disrupt the relationship at the heart of her professional life.

There didn’t even seem to be any signposts in the changes Penny had made between the drafts. There was a certain amount of linguistic tinkering, some reorganization of material, rearranging the order in which certain sections appeared. But there was no structural rewriting that went to the heart of the book. However Penny had fiddled superficially, her central storyline had driven forward with the impetus of an arrow flying from a bow.

By the time she had reached the end of the final chapter, it was after midnight and Lindsay was no nearer an answer. Whatever Penny’s killer had feared from the pages of Heart of Glass, it was far too subtle to strike her.