Here are a several things I would never do if I seriously believed my best friend in the world was brutally murdered as part of a conspiracy...
1. Reveal information from "inside sources" in such a way that would almost certainly get those sources killed if I really believed I was dealing with cold hearted murderers.
2. Slow roll details of my investigation to the public in such a way that would let the people I was investigating on to what I was looking for, where I was looking for it and who I was using inside their organization to find it.
3. Reveal critical information that could lead to their prosecution in such a way that could allow them to destroy, hide or alter evidence before it could be seized.
4. Implicate his wife and mother of his children, who he was madly in love with, without sufficient evidence.
5. Work 24/7 to destroy everything he had spent his life building, without sufficient evidence.
But those are just rules you might follow if you wanted to see his killer/killers brought to justice and protect his legacy and family...
You might do something very different if you had different motivations.