A Bay Area real estate firm under investigation by the U.S. Securities and Exchange Commission engaged in “serious misconduct” over three decades, according to a recent investor update.

The SEC opened a fact-finding inquiry into Novato-based Professional Financial Investors Inc. after company founder Kenneth J. Casey died last month. In June, the firm asked all of its corporate officers to resign and appointed Michael Hogan of Armanino as chief restructuring officer of PFI.