1. Check and verify structural integrity of wooden framing members.
2. Repair or replace structurally compromised materials.
3. Using forced air, dry the effected area completely. If possible, introduce a light source, the more UV the better.
4. Spray affected area with undiluted Clorox bleach, generously. Treat the area around the mold for at least 12 inches.
5. Repeat drying process.
6. Seal affected area with a fungicidal paint, like Killz. Personally, I recommend Zissinger's Bullseye 1-2-3, which is a polyelastomer based primer, something that will stop gas exchange and thus the respiratory function of any remaining mycelium.
I did professional mold remediation for several years, that is the approved process for the murder of black mold and other gunky nastyness.