Sure you do. And if you don't, just think of all the fun you'll have, and all the things you'll learn, doing the research.
Book reviews are essential, but articles are the heart of any good journal.
You can throw in some mainstream historical fiction, refer to some good reference books, annotate some interesting web sites. Throw in a little Burns and Roberts to spice it up. A look at Faye Kellerman, Sharan Newman and Maan Meyers for some insight into the relationship of Jews with the rest of society. The fascinating thing about historical mysteries is that we get an opportunity to peek at just about every aspect of human thought and endeavor throughout a great deal of recorded history, and you can expand, expound and explicate on whatever happens to interest you. Make it straightforward, funny, thoughtful, scholarly.