A point of sale system capable of operating in an indicia-reading mode or a verification mode is disclosed. In the indicia-reading mode, the point of sale system configures its illumination, imaging, and processing to read indicia as part of a normal checkout process. If triggered by a user or by an event, the point of sale system may operate in a verification mode. In the verification mode, the point of sale system enables the necessary illumination, imaging, and processing to verify an item. This verification includes illuminating the item in a way that causes a noticeable response from a security mark (or marks) on the item. An image of the response may be captured and processed to authenticate/verify the item. The point of sale system may then respond to the verification and/or may store the image/results as a record of the verification.