Ken Klippenstein, Eric Lichtblau

Within hours of the storming of the Capitol on January 6, the FBI began securing thousands of phone and electronic records connected to people at the scene of the rioting — including some related to members of Congress, raising potentially thorny legal questions.

Using special emergency powers and other measures, the FBI has collected reams of private cellphone data and communications that go beyond the videos that rioters shared widely on social media, according to two sources with knowledge of the collection effort.

In the hours and days after the Capitol riot, the FBI relied in some cases on emergency orders that do not require court authorization in order to quickly secure actual communications from people who were identified at the crime scene. Investigators have also relied on data “dumps” from cellphone towers in the area to provide a map of who was there, allowing them to trace call records — but not content — from the phones.

The cellphone data includes many records from the members of Congress and staff members who were at the Capitol that day to certify President Joe Biden’s election victory. The FBI is “searching cell towers and phones pinging off cell sites in the area to determine visitors to the Capitol,” a recently retired senior FBI official told The Intercept. The data is also being used to map links between suspects, which include members of Congress, they also said. (Capitol Police are reportedly investigating whether lawmakers helped rioters gain access to the Capitol as several Democrats have alleged they did, though Republican officials deny this.)