Sleuths Read Old Booby-Trapped Letters Without Opening Them

People once folded their correspondence in intricate ways, known as “letterlocking,” to keep out snoops. A fancy new imaging technique sees right through it.

Sleuths Read Old Booby-Trapped Letters Without Opening Them
People once folded their correspondence in intricate ways, known as “letterlocking,” to keep out snoops. A fancy new imaging technique sees right through it.