In this case, get a lawyer and don't answer any questions without them. Also, if you do leak a hard copy, print it at a public place and use a B&W printer. Color printers are relatively easily traced.
Are those tracking dots not microscopic? I would assume printer manufacturers also put them on black-and-white prints. Even if they don’t do it now, this is only a printer driver update away.
They are very small, but not microscopic. They are done in yellow ink, which is why they are very hard to see. If they were printed in black ink, I think you'd be able to spot them immediately, despite their small size.