(Cambridge, MA)  --  Vice President Joe Biden vows that the U.S. will never be intimidated by terrorists.  Biden spoke today at a memorial service for Sean Collier, an MIT police officer believed to have been gunned down by the two Boston Marathon bombing suspects. 

Biden said terrorists are losing around the world and called the two suspects cowardly, twisted and perverted.  Biden called Collier a true hero.  He saluted the bravery of all law enforcement officers.  The Vice President also cited the bravery of Bostonians and said Boston and the U.S. will never yield to terrorism.