Rewrite, again

I am rewriting my first novel for what feels like the eighty-seventh time. I have kept a copy of each major rewrite from the first, in which there was no murder, to this one where the murder is about a quarter of the way through. At one point I had the murder on page three, but it keeps working its way back. I need to find the proper place and keep it there.
Popular wisdom has it that the murder has to be on page one to hold the readers interest, but in most of the books I read, it comes fifty or so pages into a 200 page book.
This time I may have cheated some. There is an earlier death that has a major impact on the protagonist, but had been dealt with only as back story. In this revision, that death is the subject of chapter one. Now I have to decide how I am going to handle that particular incident as I move forward. Do I have it be the overarching plot of a series of books? Do I have the perpetrator caught and punished before the end of this book? Do I ignore it altogether?