A method of theft prevention and detection includes detecting movement of warehoused product by a person using one or more cameras; obtaining a first thermal image of a body of the person, with the one or more cameras, while the person is handling or moving the warehoused product; storing a physical size or shape of the warehoused product; obtaining a second thermal image of the body of the person, with the one or more cameras, subsequent to the obtaining of the first thermal image; determining thermal intensity differences by comparing the first thermal image of the body of the person to the second thermal image of the body of the person; detecting potential theft when the thermal intensity differences correlate to the physical size or shape of the warehoused product; and informing the person that the potential theft has been detected.