A group of Democratic members of Congress have written to the Securities and Exchange Commission to call for an investigation into Elon Musk over allegations that the billionaire may have misled investors in his brain-chip company, Neuralink.

The letter was originally reported in Reuters. In the document, Reps. Earl Blumenauer of Oregon, Jim McGovern of Massachusetts, and Barbara Lee and Tony Cardenas of California reference several high-profile reports to do with Neuralink’s animal testing.