Mayor Daley and the Chicago police force.
"...The climax came Wednesday night, as a melee broke out near the Conrad Hilton Hotel across from Grant Park, and police began beating bystanders as well as protesters, using clubs, fists, knees and Mace. Some militants fought back with their own caustic sprays, bottles and concrete chunks, enraging police all the more. Officers pushed people through a plate-glass window and then, according to witnesses, attacked the dazed victims as they lay amid broken glass. A group of police cheered a soldier as he bashed a demonstrator and attacked a photographer who filmed the scene. About an hour later, film of the violence was shown at the Amphitheatre, with the effect of a thunderbolt. Sen. Abraham Ribicoff, at the podium to place Sen. George McGovern's name in nomination, decried the use of "Gestapo tactics." A livid Mayor Daley stood up as TV cameras zoomed in but what he shouted has never been precisely determined. Later that night, as the riots continued, Sen. Hubert H. Humphrey of Minnesota easily won the nomination. There were hundreds of injuries, but no deaths. A national inquiry chaired by Chicago Crime Commission director Daniel Walker, later elected governor of Illinois, called the confrontations a "police riot."
http://www.chicagotribune.com/topic/politics/elections/democratic-convention-%281968%29-EVHST000046.topic
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The National Guard murdering in cold blood four students at Kent State.
"In response to Nixon's announcement of a new invasion, students across the United States began to protest.
Protests by students at Kent State University in Kent, Ohio began on May 1, 1970. At noon, students held a protest rally on campus and later that night rioters built a bonfire and threw beer bottles at police off campus. The mayor declared a state of emergency and asked the governor for help. The governor sent in the Ohio National Guard.
On May 2, 1970, during a protest near the ROTC building on campus, someone set fire to the abandoned building. The National Guard entered the campus and used tear gas to control the crowd.
During the evening of May 3, 1970, another protest rally was held on campus which was again dispersed by the National Guard.
All of these protests led up to the deadly interaction between Kent State students and the National Guard on May 4, 1970 which is known as the Kent State Shootings or the Kent State Massacre.
On May 4, 1970, another student rally was scheduled for noon at the Commons on the Kent State University campus. Before the rally began, the National Guard ordered those congregated to disperse. Since the students refused to leave, the National Guard attempted to use tear gas on the crowd.
Because of the shifting wind, the tear gas was ineffective at moving the crowd of students. The National Guard then advanced upon the crowd, with bayonets attached to their rifles. This scattered the crowd. After dispersing the crowd, the National Guardsmen stood around for about ten minutes and then turned around and began to retrace their steps.
For an unknown reason, during their retreat, nearly a dozen National Guardsmen suddenly turned around and began firing at the still scattered students. In 13 seconds, 67 bullets were fired. Some claim that there was a verbal order to fire. Four students were killed and nine others were wounded. Some of the students who were shot were not even part of the rally, but were just walking to their next class."
http://history1900s.about.com/od/1970s/qt/kentstate.htm
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Timothy McVeigh
"On April 19, 1995, at 9:02 a.m., an explosion ripped through the Alfred P. Murrah Federal Building in Oklahoma City, Okla. It was the worst terrorist attack ever undertaken on American soil. The blast killed 168 people - 19 of them children - and injured hundreds."