Brown leather briefcase with initials AS inside

Yesterday around 3pm I realized my brown leather briefcase was missing. It's a genuine leather, about 14 inches wide with a sturdy handle and a small scuff on the bottom edge. Inside there’s a red fabric lining and a brass plate with my initials AS on the inner pocket; I also kept a faded photo of my grandfather tucked in the zippered section. I was at the Kalamazoo Public Library on Rose Street, near the entrance to the cafe, when I last saw it after stepping outside for a call. It holds work documents and a USB drive, and it has real sentimental value to me—really need it back.