WASHINGTON — House Democrats released another round of information on Friday that raised questions about elements of the impeachment inquiry, including allegations about the surveillance of the United States ambassador in Ukraine and efforts by an aide to a top congressional Republican to pursue investigations sought by President Trump.

The information came from the electronic devices of Lev Parnas, the businessman who worked with the president’s personal lawyer Rudolph W. Giuliani to pursue the pressure campaign on Ukraine at the center of the impeachment trial.

Mr. Parnas, who is facing federal campaign finance charges in Manhattan, has publicly turned on Mr. Trump and his allies. He petitioned the court to allow him to release the information to Congress, and has offered to testify in the impeachment trial and to cooperate with prosecutors in New York investigating Mr. Giuliani. And he undertook a media tour of sorts this week in which he claimed that the president “knew exactly everything that was going on that Rudy Giuliani was doing in Ukraine.”

House Democrats have been releasing the contents of Mr. Parnas’s devices over the past week in an effort to bolster their demand that witnesses be permitted to testify in the Senate trial.