Moisture Comes First, Always
Without moisture, mold cannot grow, which is why cleaning it up while the leak continues just resets the clock. That source might be a slow drain leak under a sink, a failed window flashing, a crawlspace with no vapor barrier, or a bath fan venting into the attic.
A good remediation scope names the source and either includes the repair or tells you who needs to make it. If the problem is a plumbing leak or roof flashing, a plumber or roofer may need to come first.
Dispatcher tip: Ask whether the clearance test will be done by an assessor who is not connected to the remediation company. Buyers and their agents tend to trust that report far more.