Cops

Protesters Hold Vigil And March Over Death Of Freddie Gray After Police Arrest...BALTIMORE, MD - ARPIL 21:  Protestors walk toward Baltimore Police Department's Western District police station during a march and vigil over the death of Freddie Gray, April 21, 2015 in Baltimore, Maryland.  Gray, 25, died from spinal injuries on April 19, one week after being taken into police custody. (Photo by Drew Angerer/Getty Images)

Drew Angerer/Getty

Protestors walk towards Baltimore Police Department’s Western District police station during a march and vigil over the death of Freddie Gray in Baltimore, Maryland 

WATERTOWN, MA - APRIL 19:  Police with guns drawn search for a suspect on April 19, 2013 in Watertown, Massachusetts. Earlier, a Massachusetts Institute of Technology campus police officer was shot and killed late Thursday night at the school's campus in Cambridge. A short time later, police reported exchanging gunfire with alleged carjackers in Watertown, a city near Cambridge. It's not clear whether the shootings are related or whether either are related to the Boston Marathon bombing.

Mario Tama/Getty

Police with guns drawn on Friday search for a suspect in Watertown, Massachusetts. A Massachusetts Institute of Technology campus police officer was shot and killed late on Thursday night at the school’s campus in Cambridge. A short time later, police reported exchanging gunfire with alleged carjackers in Watertown, a city near Cambridge.