University of South Florida doctoral students Zamil Limon and Nahida Bristy have been missing for more than a week, and law enforcement is asking the public for help locating them. Limon and Bristy, both 27, were last seen on April 16 in the Tampa area, the university's police department said. The two are a couple from Bangladesh. Zubaer Ahmed, Limon’s younger brother, told WTVT in Tampa that Limon and Bristy were discussing a potential marriage but were focusing on finishing their degrees