The materials show that Parnas was in constant communication with Giuliani and also Ukrainian officials as he worked as an intermediary.
Among the documents is a screenshot of a previously undisclosed letter from Giuliani to Zelensky before he took office.
In the letter, Giuliani announced himself as Trump’s personal lawyer and requested a meeting with Zelensky “as personal counsel to President Trump and with his knowledge and consent”.
The documents − including phone records, texts and flash drives turned over by Parnas − were sent to the House Judiciary Committee by three other House committees “to be included as part of the official record that will be transmitted to the Senate along with the Articles of Impeachment”, according to a statement.
Some of the materials were made public while others were marked as sensitive.
In a statement, four Democratic House committee chairmen said that they had continued their inquiry so the House impeachment managers “can present to the Senate the most complete factual record possible” before the impeachment trial.
“Despite the president’s unprecedented and sweeping obstruction of our impeachment inquiry, we have continued to collect additional evidence relevant to the president’s scheme to abuse his power by pressing Ukraine to interfere in the 2020 election for the president’s benefit,” wrote House Intelligence Committee chairman Adam Schiff, House Foreign Affairs Committee chairman Eliot Engel, House Oversight and Reform chairwoman Carolyn Maloney and House Judiciary Committee chairman Jerrold Nadler.
Parnas and his business partner, Igor Fruman, both US citizens who migrated from the former Soviet bloc, were indicted last year on charges of conspiracy, making false statements and falsification of records. Prosecutors allege they made outsize campaign donations to Republican causes after receiving millions of dollars originating from Russia.
Among the documents released on Tuesday is a handwritten note on stationery from the Ritz-Carlton hotel in Vienna that says “get Zalensky to Annonce [sic] that the Biden case will be Investigated”.
In a letter outlining the evidence, the Democrats said that Parnas’ lawyer confirmed that Parnas had written the notes.
Several of the documents show Parnas communicating with Giuliani and another lawyer, Victoria Toensing, about the removal of Marie Yovanovitch, who was at the time the US ambassador to Ukraine.
Her removal, pushed by Trump, was at the centre of the Democrats’ inquiry. Yovanovitch testified in the House impeachment hearings and said she was the victim of a smear campaign.
On April 23, the day before Yovanovitch was directed to return home, Giuliani texted Parnas, “He fired her again.”
Parnas texted back, “I pray it happens this time I’ll call you tomorrow my brother.”
The release of documents comes after a federal judge this month said that Parnas could turn over documents to Congress as part of the impeachment proceedings.
Democrats voted in December to impeach Trump for abuse of power and for obstruction of Congress.