The New York Times reported that ex-Trump advisor Stephen Miller was among 12 people who were subpoenaed to appear before a federal grand jury this week.
The Department of Justice probe is said to be centered around attempts to send fake electors to Congress as well as fundraising activities performed through his Save America political action committee, The New York Times reported.
The list of those subpoenaed included some of Trump's top officials, such as Brian Jack, the former White House political director and advisor to Trump. It also included the Trump campaign's chief financial officer and the former chief of staff for Ivanka Trump. A subpoena does not indicate that these individuals are under investigation.
Brian Jack has remained as an advisor to Trump, while Stephen Miller tweeted, "Violent criminals lay waste to our communities undisturbed while the immense power of the state is arrayed against those whose only crime is dissent.
The law has been turned from a shield to protect the innocent into a sword to conquer them." shortly after the subpoenas were served.
The Save America PAC, which was formed in the following days after Trump was defeated, has brought in more than $135 million in donations. As of the end of July, the PAC was reported to have just shy of $100 million in cash available.