I think it's more of an investigation into how the call proceeded. There was some misunderstandings because the agency that responded to the call were not aware of the details surrounding the initial 911 call. Because they didn't have that information, they had to go off the statements of an eyewitness and mistakenly concluded that Gabby was the aggressor. Had they known the details of the 911 call (that Brian had been witnessed slapping and hitting Gabby repeatedly) the situation may have been handled differently. I don't see this as a blame game, but more of a making sure this kind of incident is less likely to happen again.