Great work. A good oversight and fraud detection unit should use your data as a starting point regarding where to look.
The next part should be marrying tax documents (# of employees, expenses, salaries, etc.) to those specific companies. Any business doing a volume greater than 100K/month is going to need more than one employee.
Other things of concern:
Lifestyle to income ratio for the business: Why are some of these businesses operating out of apartments when they make over 100K/month? Does Maine have the largest group of Healthcare providers who prefer humble lifestyles?
Notoriety: If these businesses don't advertise or have pubic level awareness then how are their customers finding them? Are they on a designated list of potential in-home providers that is widely circulated in the medical community? If not, they have the best word-of-mouth advertising system ever.
Again...GREAT WORK!
Keep shining light in those dark places. It's time to make the critters run for cover.