"During the time that the FBI was putting – that DOJ and FBI were putting together the FISA (surveillance warrant) during the time prior to the election – there was another source giving information directly to the FBI, which we found the source to be pretty explosive," said Rep. Jim Jordan, R-Ohio.
Meadows and Jordan would not elaborate on the source, or answer questions about whether the source was a reporter. They did stress that the source who provided information to the FBI’s Russia case was not previously known to congressional investigators.
Source to be pretty explosive, Trump campaign member/ links to foreign entities?
https://www.foxnews.com/politics/top-fbi-lawyer-baker-offers-explosive-testimony-on-abnormal-handling-of-russia-probe-into-trump-campaign-lawmakers
List of those in the Trump campaign.
https://ballotpedia.org/Donald_Trump_presidential_campaign_key_staff_and_advisors,_2016