Mold, Mildew, Plumber

[CJ B.]

Hello Everyone.

Here's the scenario-

I am managing one of my rentals from another state. 

I have a maintenance guy, as needed, who can deal with almost everything with the exception of plumbing. 

As it turns out, I had a leak under the tub in the bathroom. The leak was leaking into the dirt filled crawlspace, which naturally created some water, which led to a smell, which led to the discovery of the leak itself.

Enter the plumber. The plumber goes into the unit, fixes the leak, and then proceeds to TELL THE TENANT (caps necessary) that the landlord (me), needs to hire a disaster clean-up company because he sees the presence of MOLD. 

Now enter the hysterical tenant who emails me everything that the plumber told her, who is basically threatening to move if I don't address this immediately. 

Obviously, I am upset with the plumbing company that they would discuss anything with my tenant, and secondly I'm just not sure the best way to proceed on this. 

I know the word "MOLD" can carry an apocalyptic connotation to tenants, and I certainly know that there is not any mold anywhere else (that I know of). 

Could it be mildew? Maybe it is mold? Can it be treated DIY? Should I run to the phone and get disaster clean-up on the line ASAP? There is a lot of conflicting information online about this scenario. 

Any thoughts on this from the BP community would be great! 

Thank You!