Honestly, I think TMZ is the perfect outlet for this. Savannah Guthrie is a celebrity, well liked and well known. She was literally getting ready to co-host the Olympics. I used to work in MSM and we monitored TMZ. Everyone does. They have built a highly successful model at being The First. Things are slower at, say, NBC. For one, how do you even contact them. New York offices? Corporate offices? Local affiliate? The process is more sluggish and also dangerously chaotic in a high profile story like this. (When Gabby Giffords was shot in Tucson, we started hearing conflicting information that she had died in surgery. We refused to air it though some other outlets, famously NPR, announced she had died. They are highly reputable so it created a domino effect of other big outlets, siting NPR, reporting she had been killed along with 6 others who tragically did die on that day. They apologized for making a "serious and grave error" by rushing the story.
https://www.npr.org/2011/01/09/132785205/editors-note-on-nprs-giffords-coverage)
But TMZ is built for speed and amplification. Because they make it easy. They aren't subtle. Their verbiage yells at you:
Send TMZ a Hot Tip!
A producer/editor gets the tip (letter, in this case), they run it through rapid legal review, use careful wording (alleged, sources, which is exactly what they used in their headline, 'Alleged Ransom Note for Nancy Guthrie...') and then use their enormous bullhorn to push the story to their huge audience. Their experience, legal strategy, and deep pockets allow them to tolerate a much higher level of risk than the legacy outlets.
TLDR: TMZ is built for this.