Moldy odor but no visible signs
We have had a musty/moldy odor in an upstairs bedroom and bathroom for the past 6 months but there are no visible signs inside or outside. Have had a mold remediator remove part of the walls under the windows in each room and covered exposed walls with antimicrobial paint. Roofing companies checked the roof and attic but both are okay. Home inspector used a moisture meter to determine moisture level in rooms. Had air ducts and carpet cleaned. Used mold inspection kit and sent to labs to determine types of mold spores. Nothing indicates that there is a significant level of mold. Musty/moldy odor still exists. Had someone out to talk to us about ozone generator. Reports are not good about this method of odor elimination. Not sure what to do next but are considering an air purifier. Would appreciate any suggestions for next steps.