The Odd Job by Charlotte MacLeod

In ten words or less: Museum director/forger murdered; security guard is arrested. Sarah investigates.

Review: When the director of the Wilkins Museum is found murdered, stabbed to death with an antique hatpin, Sarah Kelling Bittersohn is shocked. And when the murder weapon is found in the Bittersohn's office and an obituary announcing Sarah's death appears in the Boston Globe, it's time to investigate.
The museum has been involved in a scandal years before, when it was discovered that many of its paintings were forgeries. The new head trustee has accused Sarah's husband Max of falling down on the job of recovering the museum's stolen art and has accused a mild-mannered security guard of the murder.

Why bother? Sarah Kelling Bittersohn and her far-flung family of eccentric Boston bluebloods take on the world of art forgeries. Sarah and Max give Nick and Nora Charles a run for their money.