Blue hardcover mystery novel, dog-eared

I lost my blue hardcover mystery novel yesterday around 3:15pm near the Des Moines Public Library on Grand Ave, by the main entrance where the magazines are kept. It's a 320-page Penguin Classics edition, with a worn spine and the corners slightly bumped. There’s a small bookmark ribbon with a leaf charm tucked inside and a tiny coffee stain on the bottom edge. I also wrote a short note to myself on the back page and there’s a barely visible feline doodle in the margin. This book was a gift from my sister and has sentimental value; I really need it back. If you’ve seen it, email [email protected] with any info.