Blue hardcover mystery novel with worn dust jacket

I lost my blue hardcover mystery novel yesterday around 3pm, probably at the Grace Hudson Museum on Main Street in Ukiah. It's a sturdy blue cover with a worn dust jacket and a small coffee stain near the bottom edge. Inside the front cover there's a fox-shaped bookmark and a pressed fern tucked between pages 128 and 129. It was a gift from my aunt, so it's got sentimental value and I really need it back.