The fastest and simplest way is to ask them directly by calling or emailing. Searching for information about private legal entities, while possible, is inconvenient and usually incomplete/sparse.

But why would they respond with that information?

PE already has a pretty bad press, so they know that customers are calling only because PE is a red flag.

They could just serve some meaningless half-truth and try to confuse you.

PE often doesn’t care because most folks don’t know what is going on. Private practitioners are usually proud of it.