Returned to property to continue investigation of reported moisture in bathroom wall. Two exploratory openings were made to expose the 3” drain stack. Moisture was observed on the drywall approximately halfway up the wall, while the upper portion remained dry. No active water was observed on the piping at the time of inspection. All fixtures in the upstairs master bathroom (shower, toilet, and lavatory) were operated for approximately 15 minutes to test the system under load. No active leaks were observed from the drain or water lines during testing. An additional exploratory opening was made in the adjacent living room to inspect nearby plumbing, including PVC and copper lines. No leaks were found, and the surrounding drywall in that area was dry. Remediation company has evaluated the area and is scheduled to remove affected drywall, flooring, and vanity to allow for further inspection and access. At this time, no additional areas of the home show signs of moisture beyond the bathroom