National Park Service won't release a single page of the Law Enforcement Investigation?

There was a man who was found dead in Yosemite Park recently. I have filed a FOIA request with the National Park Service (NPS) for the law enforcement investigation into his death and they won’t release a single page. I am also the publisher of a real, “print” newspaper, but have not yet been into this territory with FOIA stuff. Here’s a link to the request and the denial. Is this unheard of? The NPS won’t release a single page, saying that the privacy of surviving family members trumps anyone’s right to know about the law enforcement investigation. Here’s the link to my request and the NPS reply on Muckrock: https://www.muckrock.com/foi/united-states-of-america-10/law-enforcement-report-on-the-death-of-timothy-nolan-23937/