(CNN) -- House Democrats are seeking documents from Vice President Mike Pence as part of their impeachment investigation into President Donald Trump and his conversation with the President of Ukraine. The demand for documents came in a letter Friday from House Intelligence Chairman Adam Schiff, House Foreign Affairs Chairman Eliot Engel and House Oversight Chairman Elijah Cummings. The Intelligence Committee has taken the lead on Democrats' impeachment inquiry. "Pursuant to the House of Representatives' impeachment inquiry, we are hereby requesting that you produce the documents set forth in the accompanying schedule by October 15, 2019," the chairmen wrote. Rather than traveling to Warsaw, Poland, last month to meet with Ukrainian President Volodymyr Zelensky, Trump decided to stay home to track the damage from Hurricane Dorian. In his place he sent Pence, whose face-to-face meeting with Ukrainian President Volodymyr Zelensky now puts him at the heart of events that led to the impeachment inquiry by the House of Representatives.