. >> investigators tested the letters with ninhydrin, a chemical solution that reacts to the amino acidsafter it was applied, the documents were dried thoroughly. scientists found numerous fingerprints on the two documents, but none matched brad brisbin. they weren't larry moore's fingerprints, either. next the letters were analyzed by a forensic document examiner. both letters were typed with the same typewriter. the paper was inexpensive, the kind often used in high schools. the type showed no defects, making it difficult to identify the typewriter used to create them. and only the signature was handwritten. >> the signature itself is a full cursive signature. it is full of tremor. it looks labored and it looks slow, and it does not look like it is the product of habitual movement. >> experts compared this questioned signature to several documents brad signed shortly before his disappearance. >> the upper case b in the name brad was actually constructed in three pieces. there is a break. it has the up and down spine on the left side of the letter, but between the top and the bottom of