This is a partial transcript of "The Big Story With John Gibson," August 21, 2006, that has been edited for clarity.
JOHN GIBSON, HOST: DNA tests could produce the quickest resolution to this decade-old mystery, but handwriting samples are also helping investigators determine if they have got JonBenet's real killer in custody.
Many handwriting experts have been taking a close look again at the infamous ransom note, and now they are comparing that scrawl with one in a high school yearbook Karr signed in the 1980s. Is it the same penmanship?
Some analysts are pointing out the striking similarities of the letters, particularly the letter A. John Hargett is not so sure. He's a former handwriting expert with the U.S. Secret Service.
So John, what we have is two exemplars, right? We have the ransom note and we have got Karr writing in a high school yearbook. Are they similar?
JOHN HARGETT, FORMER HANDWRITING EXPERT FOR U.S. SECRET SERVICE: They are not really that similar, and let me tell you why I say that.
The writing in the yearbook is a very flourished, it's very decorative type writing. It's probably not something that would be the typical product of a person that they would use for the rest of their life, whereas though, if you go to the ransom note, it's again, it's printing but it's more consistent with printing that you would expect to find a person doing.
GIBSON: Well, do you have some theories about whether a person's handwriting remains the same or changes over the years?
HARGETT: Well, handwriting, once an individual establishes their own style of writing, typically it remains pretty much the same, unless it's influenced by such things as drugs, or alcohol, or some type of physical impairment.
In this particular instance, the writing that appears in the yearbook is very consistent with something that is produced by a younger individual when they are still experimenting with their handwriting and haven't quite developed that system that they're going to use probably for the rest of their life.
GIBSON: So you would not make a link between these two examples of handwriting?
HARGETT: Well, again, I don't think with the material that we have at this point, we're in a position to state one way or the other whether the individual did write the ransom note. Even though there are perhaps some isolated similarities, the similarities that do appear, quite frankly, they may be not all that unusual.
I've certainly seen it in the handwriting of other people, so it's one of these things where the features that we do have may be in agreement or may be not all that significant and at the same time, there are still an awful lot of differences between those two sets of writing that preclude us from making any type of determination.
GIBSON: John, what about this phraseology? I mean, he uses this "SBTC" in notes through the years, starting in high school and then going on later. It doesn't appear in the ransom note, but this "shall be the conqueror," do you see people — well, it is in the ransom note in the bottom, "SBTC," and it's in the yearbook. Is that a giveaway that the same person wrote it?
HARGETT: I wouldn't necessarily say that's a giveaway, but I have to admit that it's very interesting that the "SBTC" appeared both — "shall be the conqueror" — in the yearbook and the "SBTC" appearing on the note.
In making a comparison between those capital letters between the yearbook and the ransom note, I certainly didn't see any agreement between those letters. But just the fact that that appeared is certainly very interesting.
GIBSON: Just interesting?
HARGETT: Very interesting.
GIBSON: All right. John Hargett, a handwriting expert with the U.S. Secret Service, thanks very much.
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