Work Server Crashes

So, the server at worked crashed over the last weekend and people said a lot of the stuff was missing on the server. I really never thought nothing of it until I noticed a pattern between separate files.

In one folder on the server there are a number of PDF files documenting employee new hires, suspension, etc. The PDF files for October through December in 2018 are missing. These same files are almost all completely missing for 2019 except for the month of May. I did not find anything weird about this until I looked in an excel spreadsheet file in a different folder (on the same server) that documents incidents. The excel file for 2018 had October through December missing as well. I went through all the separate folders and seemed to find the same pattern.

If they are claiming that it is a crash how could it wipe out PDF files in a certain folder for 2018 between October through December yet at the same time October through December is deleted on an incident log for the same dates which are logged in rows on the spreadsheet. This really sounds weird and purposeful, not just your regular crash. Does anyone know anything similar happening like this?