House panels considering whether to impeach President Donald Trump issued subpoenas on Monday to the Defense Department and Office of Management and Budget, the latest move in a wide-ranging investigation into how the President wielded U.S. foreign policy as a blunt instrument to pressure Ukraine into manufacturing political dirt.

The subpoenas target a pattern of events in which the Trump administration withheld $250 million in security assistance for Ukraine as Trump, his personal attorney Rudy Giuliani, and others applied pressure on Kyiv to draw up dirt on Joe Biden and discrediting the Trump-Russia investigation.

The subpoena to the Pentagon — delivered to Secretary of Defense Mark Esper — tracks with earlier subpoenas issued in the impeachment inquiry, going for reams of documents relating to Trump’s July 25 phone call with Ukrainian President Volodymyr Zelensky and communications within the government about withholding the aid.

The second subpoena — issued to the Office of Management and Budget — asks for information about the “actual or potential withholding” or “freezing” of millions of dollars in foreign aid to Kyiv, appropriated by Congress as part of the U.S. government’s support for Ukraine as it searches for a way to resolve the Russian-backed uprising in the country’s east.

The OMB’s role raises questions about whether it improperly withheld appropriations that had been designated by Congress — a focus of the document demand. Congressional investigators also want to know if the Justice Department’s Office of Legal Counsel issued an opinion regarding the delay, or if other routes were used to justify the aid’s withholding.

Both document demands have deadlines of Oct. 15.

The Trump administration released the Ukraine aid on Sept. 11, after it had been frozen for months in which it was frozen. Two days before — on Sept. 9 — the House Intelligence, Foreign Affairs, and Oversight Committees had launched an investigation into the pressure campaign on Ukraine.

The same day, the Intelligence Community Inspector General notified House Intelligence Chair Rep. Adam Schiff (D-CA) that a whistleblower had submitted a then-classified complaint.