legalfags please help.

If Huber is the US Attorney responsible for working with the Horowitz and the OIG, where will grand jury proceedings occur?

In his district or in the district where the crimes ocurred?

In other words, do we know where grand juries might now currently be considering charges?

https://www.justice.gov/usam/criminal-resource-manual-156-disclosure-matters-occurring-grand-jury-department-justice-attys