I think the point of the mystery wasn't to find when it started (although the story does heavily imply it) it's more to find what exactly happened here and with the original investigator. Did you find all the files? Including all the 00-files?
Yeah I did. I guess my point is to highlight that I thought I did it but I wasn't sure if I did!
If there was more for me to glean from the 98 files about any of those two points I missed it.
I didn't even get the 98th file until I was going through the comments here so I guess it and its secret were only an easter egg (thankfully as I wouldn't have ever completed without help otherwise).