I understand their want to play nice.
But the coroner's comment does not make it an obligation on LE's part.
If LE absolutely had any real evidence and they believed that a cop killer or killers were on the loose, they would have no obligation nor expectation of keeping the possibility of this being a suicide on the table. Let alone by making that part of a public announcement.
It isn't a question of real evidence. They just don't have enough evidence to convince Rudd to make the call of homicide. And, IMO, they have a strong suspicion of what happened and are working on it. They aren't going to share more than they have to with Rudd. They will only share enough to keep the question of homicide open to investigate. And they certainly won't share with the public. But they do have to work with Rudd in order to continue the investigation withoit the whole thing breaking down.