No, but morally they do. If I had a son-in-law who murdered my daughter and grandson and subsequently found out that he was a total liar and deceiver I would feel compelled to do the same. The Rocha's tried the polite route, then the legal route, and when they started getting the famous Peterson/Geragos run around and lies they took matters into their own hands.
Seems to me that the Rochas didn't want to wait - they had an agreement they were to abide by, and they broke that agreement. If anyone looks bad out of this, it is the Rochas...