Congress will play no role in these pending prosecutions.
The executive branch enforces the laws…
“[T]he power to investigate must not be confused with any of the powers of law enforcement; those powers are assigned under our Constitution to the Executive and the Judiciary.” Quinn v. United States (1955). “Since Congress may only investigate into those areas in which it may potentially legislate or appropriate, it cannot inquire into matters which are within the exclusive province of one of the other branches of the Government. Lacking the judicial power given to the Judiciary, it cannot inquire into matters that are exclusively the concern of the Judiciary.” Barenblatt v. United States (1959).
https://verdict.justia.com/2018/05/25/no-oversight-power-does-not-let-congress-ride-shotgun-in-criminal-investigations