The Justice Department has subpoenaed Stephen Miller, who served as a senior White House adviser under former President Trump, in its investigation into the events surrounding the Jan. 6, 2021, Capitol attack, The New York Times reported, citing people briefed on the matter.

Miller was one of more than a dozen people connected to the former president who received subpoenas this week from a federal grand jury seeking information related to Trump’s Save America PAC and alleged plans to submit slates of fake electors in an effort to overturn the results of the 2020 election, according to the Times.

The federal grand jury also subpoenaed former White House political director Brian Jack, per the outlet.

Trump’s Save America PAC was formed days after the 2020 election was called for President Biden as the former president fundraised on his unfounded claims that the election was stolen.

Several junior and mid-level aides who served on Trump’s campaign or in the White House, Ivanka Trump’s chief of staff and the chief financial officer of Trump’s 2020 campaign have also received subpoenas seeking information related to the Save America PAC, the Times reported earlier this week.

The investigation is one of many Trump is currently facing.

The former president and the Justice Department are currently tied up in a legal battle related to the department’s investigation into documents recovered from Trump’s Mar-a-Lago residence.