It’s emerged that Fiat Chrysler Automobiles [NYSE:FCAU] may be looking at a Federal Grand Jury investigation into its sales numbers.

According to Automotive News (subscription required), some of FCA’s dealers in the United States have received subpoenas to provide documents and or testimony to a Federal Grand Jury investigation into reported sales numbers. A source revealed that investigators visited FCA’s U.S. headquarters as well as all nine regional business centers. The investigators were also said to have visited former and current employees at the homes.

The automaker on July 18 confirmed that both the Securities and Exchange Commission and Justice Department were looking at sales numbers reported by its unit in the U.S., and on Tuesday, following its own internal audit, FCA said it planned to change the way it reported sales to improve transparency.

Using the new reporting methodology, FCA’s previously announced 75-month streak of sales growth in the U.S. would become a 41-month streak, ending in September 2013.

Discrepancies in FCA’s sales numbers were initially sparked in January when a pair of Chicago-area dealers filed civil lawsuits against FCA, alleging certain dealers were paid to report false sales.

We’ll provide an update as soon as more is known.