The House select committee investigating the Capitol attack on Thursday issued new subpoenas to allies of Donald Trump as well as the organization affiliated with the “Stop the Steal” rally that deteriorated into the 6 January insurrection.

The third tranche of subpoenas reflects the select committee’s overarching focus on the extent of Trump White House involvement in planning the Capitol attack, as they target entities connected to top executive branch officials and members of Congress.

House select committee investigators issued subpoenas compelling documents and testimony to Ali Alexander, a far-right activist who emerged as the chief architect of the “Stop the Steal” rally, and Nathan Martin, who was connected to permit applications for the rally.

The subpoena letters noted Alexander made repeated references to the use of violence on 6 January, and claimed to have communicated with the White House and members of Congress about plans to stop the certification of Joe Biden’s election win.

“Accordingly, the select committee seeks documents and a deposition regarding these and other matters that are within the scope of the select committee’s inquiry,” the panel’s chairman, Bennie Thompson, said in the letters.

The select committee also authorized a subpoena for Stop the Steal LLC, the corporation behind the rally. The subpoena letter demanded that the registered custodian of records for the group produce documents and appear for a closed-door deposition later this month.

The new subpoenas come a day after the Guardian first reported that Trump’s former White House chief of staff Mark Meadows, deputy chief of staff Dan Scavino, strategist Steve Bannon and defense department aide Kash Patel would resist the orders under instruction from Trump.

House investigators had issued the subpoenas to the Trump aides with the threat of criminal prosecution for non-compliance, warning that the penalty for resisting the orders would be far graver under the Biden administration than during the Trump presidency.

The argument for Trump pushing the aides to not cooperate with the inquiry is being mounted on claims of executive privilege, arguing that what the former president knew in advance about the Capitol attack should be secret, according to a source familiar with the matter.

Alexander was a key figure behind the “Stop the Steal” movement to subvert the 2020 election and said in a since-deleted video that he worked with the Republican congressmen Paul Gosar, Mo Brooks and Andy Biggs to interfere with the certification in order to reinstall Trump as president.

“We four schemed up to put maximum pressure on Congress while they were voting,” Alexander said in the video.

It was not immediately clear whether Alexander, Martin and George Coleman, the registered agent for Stop the Steal LLC, would comply with the orders. Martin and Alexander have until 21 October to produce documents, and until 28 and 29 October respectively for testimony.