Authorities in Czech Republic are searching for a motive behind a student's gun attack at Charles University's Faculty of Arts in Prague, which left 14 people dead. The gunman, a 24-year-old student, was also killed during the attack. The government has declared a national day of mourning on Saturday to honor the victims. Flags on official buildings will be flown at half-staff and a minute's silence will be observed at noon. The investigation into the shooting is ongoing.