I would like to apologize for my last post Glurk, it sounded a bit nasty. Wrote it in a bad moment.
Dave, you are right, I didn’t mean the actual cipher contents, just the reason he chose to split it into three parts as opposed to just send one cipher.

my assumption is he split it into three because he was an effective marketer (of himself). he sent it to three major publications, tied each part to the other two, and pretty much forced the hand of all three to compete with each other about the sensationalism, which gave him the publicity he desired. he also gave himself a better chance that one of the three would take it seriously and alert the other two. also, this was his first attempt at writing as the zodiac (as far as we’re aware) and he must have thought long and hard about the best way to not end up in the "kook" bin (i’m again assuming these publications get a lot of nutjobs writing in).

…also, this was his first attempt at writing as the zodiac (as far as we’re aware) …..

Yep, Mazzer, exactly, except perhaps for Riverside. Which not everyone agrees on, of course.