Printers can provide more evidence than most might suspect. Digital evidence hidden on the printed page is a wild idea. But apparently the FBI is well aware that many printers hide yellow dots on printed text that identify when a document was printed and the serial number for the printer. So, if your client paid for a printer with a credit card and then used it to create anonymous threatening letters sent to a number of important government officials, there could be an FBI knock on the door in the client’s future.
This isn’t a new idea. But if you want to learn more about it, read Why Printers Add Secret Tracking Dots.