Murder by Committee — Veronica Heley

The sixth Ellie Quicke mystery - It seemed an innocent request: would widowed Ellie Quicke visit a man whose dog died in an accident? The dog's master a powerful but unpleasant businessman believes he was the intended target, and that an old enemy is responsible. Feuding financiers are bad news not only for the City, where jobs are at stake, but also for Ellie, who can't fill in a tax return without help.