In July 2013, the movement began with the use of the hashtag #BlackLivesMatter on social media after the acquittal of George Zimmerman in the shooting death of African-American teen Trayvon Martin 17 months earlier in February 2012. The movement became nationally recognized for street demonstrations following the 2014 deaths of two African Americans, that of Michael Brown—resulting in protests and unrest in Ferguson, Missouri, a city near St. Louis—and Eric Garner in New York City. Since the Ferguson protests, participants in the movement have demonstrated against the deaths of numerous other African Americans by police actions or while in police custody. In the summer of 2015, Black Lives Matter activists became involved in the 2016 United States presidential election. The originators of the hashtag and call to action, Alicia Garza, Patrisse Cullors, and Opal Tometi, expanded their project into a national network of over 30 local chapters between 2014 and 2016. The overall Black Lives Matter movement is a decentralized network of activists with no formal hierarchy.