RALEIGH, N.C. (AP) — Federal prosecutors have served North Carolina’s environmental agency with 20 more subpoenas seeking documents and ordering 19 state employees to testify before a grand jury, part of a broadening criminal investigation into a massive coal ash spill.

The subpoenas made public by the N.C. Department of Environment and Natural Resources on Wednesday also ordered state officials to hand over any records pertaining to investments, cash or other items of value they might have received from Duke Energy or its employees.