I think the cops are going to have to release all notes.............................................. This worked on the Uni-bomber case, and many more.There is a big differance. The Uni-bomber was sending his manifesto to the newspapers and demanding that they be published.
If I recall it took quite a long time before the newspaper did this and when they finally did it was his brother who recognized the writings and turned him in.
I am not sure who the many more are that you refer to. The Zodiac killer in the San Francisco, Bay area in California 1969/70 wrote lots of letters and quite a few were published. To this day they have not learned who the Zodiac killer is/was.
IMHO I think that they should stop playing "his" game. Stop making announcements and using the media to relay messages to "him". Immediately release all the information they have on him including copies of ALL letters/tarot cards etc.
Perhaps someone would recognise the writing or better yet the manner in which he speaks. I simply don't see how continuing to go along with his demands is going to make a difference. There are people out there that are just plain evil and the sooner we accept that the better off we all will be. He obviously is without a conscience.