The first criminal trial arising from a five-year investigation into allegations of abuse at New Hampshire’s youth detention center is underway. The case involves a different state-run facility, however, in Concord. Victor Malavet of Gilford is one of nine former state workers charged in connection with the attorney general’s broad criminal probe of the Sununu Youth Services Center. His trial started Monday on allegations that he sexually assaulted a 16-year-old 12 times in 2001. Prosecutors say the 62-year-old Malavet started paying special attention to the girl soon after she arrived, coercing her into sex in a candy storage room and other locations. His attorney says the alleged victim is lying.