 Complete the following phrase:  There have been many high-profile incidents in the United States in the 1990s, 2000s and 2010s of individuals thought to be attempting suicide by cop or killing others before killing themselves. Examples include the 1999 Columbine High School massacre, the 2007 Virginia Tech massacre, the 2010 Austin plane crash, the 2012 Sandy Hook Elementary School shooting, the 2014 Isla Vista killings, and the 