Death in the Palazzo — Edward Sklepowich

In an ancient Venetian palazzo, Urbino Macintyre encounters a decades-old murder

The Contessa da Capo-Zendrini is one of the leading lights of Venice society, but there is one house where she has long been unwelcome. Her late husband's family, the Zenos, has loathed her since the 1930s, when a gathering at her palazzo ended in tragedy. Decades later, she hits on a devilish plan to make amends: inviting the Zeno clan over for a house party to make up for the one that ended in bloodshed long ago. But soon after her guests arrive, murder strikes again.
 
The contessa begs her closest friend, American sleuth Urbino Macintyre, to unravel the mystery of the killing before it tears both families apart. No one has been in or out of the house since the fête began, so the murderer must be among the guests. It seems simple, but this is Venice, where death is never easy.