I'm not Mary, obviously. My opinion: both JS and SDSO have and continue to *shade the truth*. Also imo, neither of those parties expected the Zahaus to refuse to give up their quest to have the truth of RZ's death revealed. From the very beginning, they've been trying to just make her death go away with the ruling of suicide. But the Zahaus refuse to go away, and now the shady tactics used to arrive at the suicide conclusion (by everyone interested in the suicide conclusion) are coming back to bite them on their corrupt backsides.
IMO, in case that wasn't clear.
Edited to add: As to your question of why, imo and as I've stated before, JS didn't want his image or his company's image tarnished. Why the SDSO played along is, to me, the more important and tremendously disturbing question.