Questioning the Dead
Obviously, the passengers were the first suspects, as someone on that plane was likely the person who blew it up. They searched for someone with a previous record, someone with a past twisted enough to indicate that they were capable of such egregious wrongdoing. They focused on people who were from Colorado, as a stranger to the state likely wouldn't be the culprit...
Colorado Locals
The FBI focused in on people native to Colorado. Several had taken out life insurance policies, which was usually an indicator of something dark. For the investigative team, these people stood out more than others. One woman, a passenger from the flight, caught the FBI team's attention. They had no idea how impactful her story would eventually be...