How Freezing Your Credit Impacts Background Investigations

Hmmm…thanks for the advice- I had my investigation (T5 for a BI job) begin almost 2 months ago…met with my investigator…no mention of needing my credit unfrozen to be checked.
My email got hacked and an attempted fraudulent charge ensued right before my e-quip. My data was also breached on Equifax, so they allowed a freeze for free, but I need to send TransUnion and Experian a copy of my police report to avoid the $10 charge, and I haven’t done it yet.
Any idea of which of the 3 bureaus they check? Or all three? I have ‘excellent’ credit rating on all 3, so it wouldn’t matter which they checked…