Kenneth Thompson became the first African-American to be elected Brooklyn district attorney yesterday, defeating incumbent Charles Hynes, whose effort to win a seventh term sputtered after he lost the Democratic primary and ran in the general election on the Republican and Conservative ballot lines, the Wall Street Journal reports. Thompson, 47, is the first challenger to unseat an elected district attorney in Brooklyn in 102 years. In a victory speech, he said, We must end this belief in no snitching, which allows criminals to prey on our neighborhoods.” He is a former federal prosecutor whose mother served as a New York City police officer. The loss suggests an end to the public career of Hynes, 78, who has been in office since 1990 and served longer than any D.A. in the borough’s history. During his two dozen years in office, he has been praised for his work in domestic violence, alternative-to-prison drug treatment programs and work supporting parolees’ as they re-enter society.