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.
The scope should spell out what is causing the moisture and whether that repair is included or needs another trade. If the problem is a plumbing leak or roof flashing, a plumber or roofer may need to come first.
Dispatcher tip: Make sure post-remediation testing is done by an independent assessor, not the same company that did the work. Buyers and their agents tend to trust that report far more.