§ 356 Jurisdictional limits - Investigations.

This rule makes sure that multicounty grand juries don't take away power from regular county grand juries or district attorneys. Even though multicounty grand juries can investigate crimes that cross county lines, this doesn't stop local grand juries or prosecutors from doing their own investigations.

The rule also protects investigations that are already happening. If a county grand jury or another agency already started looking into a case, a multicounty grand jury can't just step in and take over that same investigation. The only exception is if there's a good reason for the multicounty grand jury to get involved instead.

In simple terms, this rule prevents overlap and conflict between different investigators. It respects the work that local authorities have already started, while still allowing multicounty grand juries to do their job when needed.