(NewsNation) — The Justice Department is continuing to expand its inquiry into the Jan. 6, 2021, Capitol riots, issuing more than 30 subpoenas to people in former President Donald Trump’s circle, according to media reports.

Two top Trump advisors, Boris Epshteyn and Mike Roman, had their phones seized, the New York Times reported, and two subpoenas went to former campaign manager Bill Stepien and Sean Dollman, CNN reported. Dan Scavino, Trump’s former deputy chief of staff, was also subpoenaed in recent days.

The subpoenas mark a significant escalation into the DOJ’s investigation of the Capitol riots and efforts to overturn the 2020 election. Prosecutors have been probing a so-called fake electors scheme, a plan to create a slate of phony Electoral College electors pledged to Trump in battleground states he lost.

The recent subpoenas are fairly broad and seek both evidence and grand jury testimony, according to CNN. They also target the Save America PAC, the main fundraising vehicle for Trump since he left office.

Prosecutors are also seeking information about and communications with Trump lawyers Rudy Giuliani and John Eastman, according to the New York Times. Giuliani has already testified before a grand jury in Georgia about efforts to overturn the election in that state.

The DOJ’s investigation runs parallel to one also being conducted by a House committee, which earlier this summer agreed to share some of its transcripts with prosecutors. The panel held a series of public hearings this summer and is expected to issue a report on its findings sometime this fall.