Senate Judiciary Committee chairman Chuck Grassley released a letter on Tuesday accusing Fusion GPS co-founder Glenn Simpson of making “extremely misleading” statements” to Senate investigators.

Simpson told the Senate Judiciary Committee in August of 2017 that he stopped compiling opposition research on Donald Trump subsequent to 2016 presidential election. According to the Iowa lawmaker, the operative’s testimony appears to contradict statements that Daniel Jones, a Senate Intelligence Committee staffer and aide to Sen. Diana Feinstein (D-CA), gave to the FBI in March of 2017.

During the hearing, Simpson was asked, “So you didn’t do any work on the Trump matter after the election date; that was the end of your work?”

“I had no client after the election,” Simpson replied.

Grassley writes that Simpson’s statement was not only “extremely misleading” but possibly an “outright lie.”

Daniel Jones, who runs a consulting firm called Penn Quarter Group, told the FBI up to 10 “wealthy donors from California and New York” funneled $50 million into opposition research projects, reported the Daily Caller’s Chuck Ross.

“Mr. Jones stated that he was leading a research and investigatory advisory organization called the Penn Quarter Group, which ‘had secured the services Steele, his associate [redacted], and Fusion GPS to continue exposing Russian interference in the 2016 Presidential election,'” Grassley wrote to his Senate Judiciary Committee colleague Sen. Chris Coons (D-DE).

In a warning shot to Simpson, Grassley concluded his letter by stating the contradictory statements were made in “contexts where material lies are criminal.”

In April 2016, Simpson was hired by the Democratic National Committee to investigate possible collusion between Donald Trump and Russia.