CNN reporter Phil Mattingly said the Hillary Clinton campaign was "stunned" Friday by the news that the FBI was re-opening the investigation into the Democratic candidate's private email server, adding the campaign plane did not have WiFi and thus the team had no idea about the news until it landed in Iowa.

"It's kind of an incredible thing," Mattingly said. "The plane did not have WiFi during the entire flight, so you had senior advisers, as well as Hillary Clinton, on the plane, and as the plane landed they were finding out about this."

One Clinton adviser actually told Mattingly they were learning about the news at the same time as the press on the plane.

"They did not have advance notice of this. They seem similarly stunned," Mattingly said. "We saw them huddling … They clearly were not aware of this in advance."

News broke shortly after 1 p.m. ET that FBI Director James Comey sent a letter to Congress announcing that the agency was reviewing newly discovered emails regarding the Clinton case. The investigation appeared to have been closed in the summer when the government elected not to prosecute her for potential mishandling of classified information, although Comey said she was "extremely careless" with her email practices.

Clinton is speaking Friday afternoon at a campaign event in Cedar Rapids and later doing a rally in Des Moines. Iowa is one of the tightest states in the election race between her and Donald Trump.