Last Monday, the Justice Department filed around 40 subpoenas as part of its criminal investigation into the attack on the United States on January 6.
Advisers to former President Donald Trump, along with former White House officials and staffers from his 2020 presidential campaign ranging from entry-level workers.
According to the sources, the phones of at least one key Trump aide, Boris Epshteyn, were recently taken as part of this attempt.
Subpoenaed witnesses are being asked about the events preceding up to and including the attack on January 6th.
Sources say a federal grand jury is looking into the Trump PAC's beginnings and fundraising activities.
ABC News attempted to get reaction from Epshteyn, but he never got back to them.