After a clumsy response to revelations about his infamous Trump Tower meeting last summer with a Russian lawyer and alleged ex-Soviet spy, among a handful of other colorful characters peddling dirt on Hillary Clinton, Donald Trump Jr. is expanding his legal team ahead of his closed-door testimony Tuesday before the Senate Judiciary Committee.

Earlier this month, the president’s eldest son retained Alan Futerfas, a criminal defense lawyer, to help fend off allegations that he colluded with the Russian government’s efforts to help elect his father. Now, as he prepares to be questioned about the campaign’s ties to Russia, Reuters reports that Trump Jr. has also hired Williams & Jensen attorney Karina Lynch, who has previously worked on Congressional investigations and served as investigative counsel to Senator Chuck Grassley. Trump Jr. is also reportedly receiving advice from veteran Washington lawyer Fred Fielding, who served under Nixon, Reagan, and George W. Bush.

The legal duo’s expertise comes at a critical juncture for Trump Jr. Along with former campaign manager Paul Manafort, who also attended the June 9 meeting, the eldest Trump son was initially expected to appear in a public Senate hearing. Instead, Grassley, the Judiciary chair, and ranking member Dianne Feinstein announced that both men would give their testimonies in private. While the news that neither Trump Jr. nor Manafort would be under oath caused a stir online, experts were quick to note that neither will be off the hook. Closed-door hearings are generally considered a more formidable investigatory tool, allowing more time for cross-examination and less time for grandstanding. Their testimony could also create a perjury trap, since, as Grassley pointed out on Twitter, it remains a crime to lie to Congress under any circumstance. (Jared Kushner, who was also present at Trump Tower, will testify before the Senate Intelligence Committee on Monday and the House Intelligence Committee on Tuesday in back-to-back closed-door sessions. In an 11-page statement released ahead of his testimony, Kushner said he had “hardly any” contacts with Russians during the campaign and asserted he “did not collude, nor know of anyone else in the campaign who colluded, with any foreign government.”)

All three members of the Trump campaign remain in legal jeopardy as the federal investigations accelerate—not just because an expanded probe means more opportunities to uncover unrelated crimes, but because it increases the risk of committing perjury. “That is the real danger for people, William Jeffress, the white-collar defense attorney who famously represented I. Lewis “Scooter” Libby, told me in a recent interview. “It is unwise for anybody to talk to the investigators where he doesn’t know what evidence is out there, he hasn’t refreshed his recollection on what e-mails other people have or, the lawyer does that for the witness. You see it time and again in these political investigations that they wind up, whatever happened wasn’t a crime. It may have been a political scandal but it wasn’t a crime but they charged somebody with perjury or obstruction.”