The FBI has released a detailed video timeline tracking the movements of a person of interest in the Brown University mass shooting — but despite multiple camera sightings, the suspect remains unidentified. The newly released footage compiles clips from residential security cameras near Brown University, showing the suspect roaming campus-adjacent streets before the attack and walking past police vehicles shortly after gunfire erupted inside an engineering building. Two students were killed and nine others were wounded in the shooting. So why is it still a nightmare for investigators to identify the suspect?