Death on the Family Tree by Patricia Sprinkle is the first book of the Family Tree mystery series, set in contemporary Atlanta. Katharine Murray lives mostly alone in a beautifully decorated house. Her husband Tom travels extensively, always putting the job and its crises ahead of family. Her children are adults, living on their own; so Katharine finds herself alone on her 46th birthday, wondering a bit about her life's purpose. She receives an unexpected delivery - 10 boxes full of a deceased relative's possessions. Mostly junk (the old woman was a packrat) but one box marked "Carter" holds a curious brass necklace and a diary. Katharine unexpectedly runs into an old friend she hasn't seen since high school, now a university history professor. When she shows him the necklace and diary, he recognizes them as historical artifacts and wants to take possession for a museum. Katharine first wants to understand who is "Carter" and why her relative saved the items. She asks a good friend who is a genealogy buff how to do some family research. Turns out, she really enjoys digging through records. She gets surprising results - Carter was a relative in her family, never mentioned in her presence. So she digs further into family records, while enlisting her history prof friend's help to translate the diary (written in German).
Someone else is interested in the artifacts - dangerously so. Katharine experiences a break-in one night, resulting in the theft of the diary, then a few days later her house is completely trashed. She had the necklace hidden away, so it's safe, and she had made copies of the diary, so she continues with the translation and family research. Meanwhile Tom makes excuses and stays longer on his business trip, even though she is shaken and needs his support. Katharine is not quite sure who to trust, but after the murder of her genealogy pal, she has only the history prof to help her.