A law enforcement officer on a tactical vehicle watches after a device was fired to disperse a crowd Sunday, Aug. 17, 2014, during a protest for Michael Brown, who was killed by a police officer last Saturday in Ferguson, Mo. As night fell Sunday in Ferguson, another peaceful protest quickly deteriorated after marchers pushed toward one end of a street. Police attempted to push them back by firing tear gas and shouting over a bullhorn that the protest was no longer peaceful. (AP Photo/Charlie Riedel)

Missouri governor sends National Guard to Ferguson

Gov. Jay Nixon said the National Guard would help "in restoring peace and order" to Ferguson, where protests over the killing of 18-year-old…