Gustavo Petro, a former guerrilla, was elected mayor of Colombia\'s capital on Sunday. Petro defeated eight other candidates running in the race for the mayoralty and will assume office on Jan. 1 for a four-year term. Surrounded by his family and cheered by hundreds of supporters in a lounge of a hotel, Petro said, \"I want to thank Bogota... Undoubtedly this is a victory.\" Petro was a former guerrilla fighter from the April 19 Movement (M-19), which laid down weapons in the early 1990s after negotiations with the government. The re-entry into civilian life of Petro marked the start of his career in politics, and he served first as a Senator and then a House Representative. In March 2010, he became the presidential candidate for the opposition Democratic Pole (PDA). But he later quit the party after making public a corruption case. According to surveys, Bogota citizens hope the newly elected mayor would improve stability and safety in the city.