There is still a leak somewhere. It wouldn’t still be wet 5 years later without some sort of leak. I would get a plumber to stop the leak, then spray it with bleach. I wouldn’t disturb the mold spores until the insurance company sees it. Many insurance companies exclude mold damage. You might want to check that out, and maybe gather documentation that the incident happened 5 years ago. The mold exclusion may not have been in place at that time.