We're told the feds are also extremely motivated to find the people responsible for attacking Capitol PD officer Brian Sicknick ... who later died from his injuries.It's TMZ, but...We're told the FBI and the National Security Agency are using cell phone tower data, and state-of-the-art digital imaging systems to help ID people who were in the Capitol during the insurrection -- that includes rioters, Capitol staffers.
The FBI particularly wants to know if any off-duty Capitol Police officers were in the building, and if so, why.
