The extent of that surveillance coverage is now under scrutiny after a gunman killed two students and wounded nine others last Saturday before disappearing from the scene.

The Portuguese suspect in the Brown University and MIT shootings came to the United States through a little-known pathway called the diversity immigrant visa.

A tipster alerted investigators to the post, which was shared in the subreddit r/providence, that said “police need to look into a grey Nissan with Florida plates, possibly a rental.”