Parent property of ITestSuiteBase always returns null

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C#

C#4.0

TFS

We have an requirement where we are using TFS & MTM SDK we need to retrieve the test suites information.
As part of the requirement I will get the test suite id and using this I should be able to retrieve corresponding parent test suites till I reach the top. My sample code is snippet is shown below

ITestSuiteBase testSuite = teamProject.TestSuites.Find(suiteId);

List<TFSItem> suiteList = new List<TFSItem>();

if (testSuite != null)
{
    // this is the test plan
    if (testSuite.Parent == null)
    {
        suiteList.Add(new TFSItem(testSuite.Id.ToString(), testSuite.Title));
    }
    else
    {
        var tempSuite = testSuite;
        while (tempSuite.Parent != null)
        {
            suiteList.Add(new TFSItem(tempSuite.Id.ToString(), tempSuite.Title));
            tempSuite = tempSuite.Parent;
        }

        suiteList.Add(new TFSItem(tempSuite.Id.ToString(), tempSuite.Title));
    }
}

Here irrespective of the test suite type (dynamictestsuite or statictestsuite), the parent is always returning null.

Can anyone please let me know am I missing something here?
If there is any other alternative solution please let me know.

Thanks,
Kiran