This is book number 6 in the Robin Lockwood series.
In Phillip Margolin's Murder at Black Oaks, Attorney Robin Lockwood finds herself at an isolated retreat in the Oregon mountains, one with a tragic past and a legendary curse, and surrounded by many suspects and confronted with an impossible crime.
Defense Attorney Robin Lockwood is summoned by retired District Attorney Francis Hardy to meet with him at Black Oaks, the manor he owns up in the Oregon mountains. The manor has an interesting history - originally built in 1628 in England, there's a murderous legend and curse attached to the mansion. Hardy, however, wants Lockwood's help in a legal matter - righting a wrongful conviction from his days as a DA. A young man, Jose Alvarez, was convicted of murdering his girlfriend only for Hardy, years later when in private practice, to have a client of his admit to the murder and to framing the man Hardy convicted. Unable to reveal what he knew due to attorney client confidence, Hardy now wants Lockwood's help in getting that conviction overturned.
Successful in their efforts, Hardy invites Lockwood up to Black Oaks for a celebration. Lockwood finds herself among an odd group of invitees - including the bitter, newly released, Alvarez. When Hardy is found murdered, with a knife connected to the original curse, Lockwood finds herself faced with a conundrum - who is the murder among them and how to stop them before there's another victim.