Brown University has placed its campus police chief on leave as it reviews security policies following a tragic shooting. Earlier this month, a gunman killed two students and injured nine others at the Rhode Island university. The U.S. Department of Education is investigating whether Brown violated federal campus safety requirements. Also on Monday, hundreds gathered in Alabama to remember sophomore Ella Cook, one of the students killed. Authorities say gunman Claudio Neves Valente was found dead days later. Cook was remembered for her impact on campus and her Christian faith. Alabama's governor ordered flags at half-staff in her memory.