Congress is not a Star Chamber and is not a Grand Jury, its members cannot charge anybody with anything, and this constant BS grandstanding by people who should know better is ridiculous.
Congress funds the executive branch and it of course does oversight of things that it funds, such as the FBI.
If Congress thinks that it sees that crimes have been committed during the course of its oversight, Congress can send criminal referrals. So the poster's question is a good one. And it ISN'T grandstanding by the Congressman. Sheesh.
You should know better, Jim.
Congress can also specify funds be withheld until they answers and action. Either way, they have a lot of control if they have the will.