FBI agents track cell phones that pinged near the Capitol
Forensic methods used by police and intelligence go much deeper than just looking at phones near the crime scene.1. They look at phones moving towards the crime scene and going dark when getting close. This is also how you can detect secret meetings between people. They move towards the same area and shut down their phones.2. They look at suspect phone going dark anywhere around the time of the incident.3. Leaving a phone at home that is not answering calls or creating traffic during the time of interest is also a lead (if you already have a suspect).