Washington D.C. city council member and Democratic mayoral candidate Muriel Bowser gives a thumbs up to supporters before voting in the District of Columbia Democratic mayoral primary election outside precinct 65 at the Lasalle-Backus Education Campus, in Washington April 1, 2014. District of Columbia voters head to the polls on Tuesday for a crowded Democratic mayoral primary, with the incumbent facing a strong threat from a city councilor after being linked to a campaign-finance scandal. REUTERS/Jim Bourg (UNITED STATES - Tags: POLITICS ELECTIONS)