I could not disagree more.
The public knows that a murderer is still at large. They know what he looks like, in general, and they have a clip of his voice.
Knowing the cause of death or whether sexual assault is an element of the crime does not help the public keep themselves safe, it only fuels gossip and rumor.
Further, these 2 aspects of the case are known to only a few, key people such that should a tip come in which includes these details, it will raise the alert that the tip may be more credible than the thousands of others.
LE has every "right" to keep details of the crime and investigation from the public. The public had NO right to know the details of an ongoing investigation. None.