REST query to retrieve user properties returns object with null data

I am trying to retrieve user properties for various users using the GetPropertiesFor method of the sp.userprofiles RESTful API.  Through a lot of testing, I discovered that I could only retrieve properties for users that have logged into a SharePoint site in the Farm at least once.  The JSON object that returns for users that have not logged in at least once looks like this:

data : {
  config: {..},
  data: {
    d: {
      GetPropertiesFor: null
    }
  },
  status: 200,
  statusText: "OK"
}

Meanwhile, the JSON object that is returned for users that had previously logged in looks like this:

data : {
  config: {..},
  data: {
    d: {
      AccountName: domain/username,
      DisplayName: "John Doe",
      etc.
    }
  },
  status: 200,
  statusText: "OK"
}

I confirmed the that the return hinged on whether the user had logged in or not by querying a test account that had not been used.  The JSON return looked like the first example above.  I then logged into a site with that test account, and tested the query again. This time, the test account's properties and values returned, like in the second example.  I have searched at length to see if others have experienced this and have found nothing. I need to be able to return user properties and user profile properties for users that have not logged in.  Thanks in advance.