Two stern-faced officers barged in, as if to apprehend a couple of criminals.

NPR: Lang Lang: A Life In Music, So Far

The primary task for law enforcement after such an attack is to identify the perpetrator(s), apprehend them, and examine whether this attack was a one-off or the first in a series.

WSJ: William Bratton: A Cop's-Eye View of Terrorism

In 2011, two team members helped apprehend a Somali man who prosecutors say is the highest-ranking pirate whom federal officials have ever captured.

NPR: FBI: Agents Fell To Deaths Training Off Va. Coast