Thank you for the pictures.
I have concern that you may have a mold issue behind your drywall. Any building material that stays wet for more than 24 hours becomes a breeding area for mold. The longer the area stays wet, your percentage of having mold goes up. The toxic black mold everyone talks about in the media typically grows on building material that is wet over time.
So, you should have someone in the mold/environmental services inspect the area with a scope.
The last thing you want to do is disrupt mold behind walls in an uncontrolled area because the activity will release mold spores into the air in your basement which can not only have negative health effects, but you can spread the mold to other areas of the home. There are certain things a home owner can do, I do not think an untrained person should deal with mold.
This is very serious and if you would like to discuss this by telephone, you may email me at [email protected]
with your information. If you would like, I can help you find and decide on a mold contractor by reviewing the proposals.