There are reputable companies out there that perform forensic accounting.
Accountants who do this work are known as Certified Forensic Accountants.
There is at least one organization that certifies these people: The American College of Forensic Examiners International.
They are here: http://www.acfei.com/about_acfei/
As far as I know, neither CPAs, Certified Forensic Accountants nor members of ACFEI do any Real Estate or Mortgage work.