Red paperback mystery with yellow bookmark

Hey, I lost my red paperback mystery yesterday around 3pm. It's a Penguin Classics edition, about 320 pages, 6x9 inches, with a slightly faded red cover and a yellow Post-it bookmark tucked inside; there's a small coffee stain on page 128 and a pencil doodle of a compass on the inside cover. I last saw it near the Fargo Theatre on Broadway, Fargo, ND, out front by the ticket booth while I grabbed a quick coffee. It was a gift from my grandmother and has sentimental value—the kind of thing I doubt I can replace. If you found it, shoot me an email at [email protected] so we can figure out how to get it back.