Grassley was supposed to take back chairmanship but I don’t remember when.
The senate hearing works very similar to a grand jury. They are an investigative body. The senate can not indict. Only refer to the DOJ. After the Senate investigate they have the option to turn the case over to the DOJ to press charges IE be tried in court ! They have NO power to indict.
Since LG is not investigating through the Senate it means that the DOJ is already past this stage They DOJ have the power through a Grand Jury (who can recommend indictments — charges be filed). OR because they actually have evidence of crime to indict (press charges) without further step.