Real estate empire the Kushner Companies has been served with a grand jury subpoena relating to paperwork practices dating to the period when White House Senior Advisor and presidential son-in-law Jared Kushner served as CEO.

An Associated Press (AP) investigation last month revealed that the Kushner Companies repeatedly filed forms with the New York City Department of Buildings claiming they owned no rent-controlled units while actually possessing hundreds of such units in Queens, New York apartment buildings they purchased in 2015.

Those filings reportedly allowed the Kushner Companies to raise rents and, in turn, sell those buildings at a great profit two years later, at which point Jared was no longer at the company's helm, but serving in the Trump administration alongside his wife, Ivanka Trump.

On Thursday, a grand jury serving under the auspices of federal prosecutors from the Brooklyn-based U.S. Attorney's Office for the Eastern District of New York approved subpoenas based on that AP report, demanding documentation as to how the allegedly false forms were prepared and by whom.