According to a Wall Street Journal article on Aug 3, Special Counsel Robert Mueller has impaneled a grand jury in Washington to investigate Russia’s interference in the 2016 elections. Several news organizations have also reported that in recent weeks Mueller has been issuing subpoenas through federal grand juries in D.C. and Virginia to both evaluate and add to the evidence investigators have obtained about the Trump team’s ties to Russia. In this Q&A, Stanford Law School Professor David Alan Sklansky breaks down the grand jury process and explains what Mueller and his team are doing.

What is the purpose of a grand jury?

In theory, grand juries have two roles:  they decide, in felony cases, whether there is enough evidence for someone to be charged, and they issue subpoenas for documents and for testimony.  In practice, though, grand juries almost always follow prosecutors’ recommendations about whether to issue an indictment, so the real importance of grand juries is as an investigative tool for prosecutors.

Is this the normal course of things for a special investigation—or is the use of grand juries a sign that his inquiry is growing?

It is absolutely the normal course of things for any complex criminal investigation in the federal system.  What would be surprising is if Mueller decided not to use a grand jury.