Yes, I hope I'm mistaken also. I hope the article is true and the obstruction indictment is just the foot in the door to get that last bit of info to get him on murder.
Indicting him for obstruction sounds like the perfect plan here. They can now proceed to question him in depth and possibly get their hands on various records he's refused to turn over.
And more importantly, I don't think prosecutors would be required to share their evidence on the murder itself with his team -- just the evidence supporting the obstruction charge.