If they aren't willing to provide transparency and full disclosure - allowing you to complete your due diligence - you might be better off to move on.

In other words - based on their elusive behavior and lack of willingness to cooperate - the egg you are looking to crack is likely a rotten one.

Of course you can always try to get this info from the broker (it wasn't clear in your description whom you requested the info from - the owner(s) or the broker). If they are uncooperative then the whole deal should be rejected by YOU.

In any case - Best of luck!