San Jose police searched for a gunman who killed a 16-year-old Japanese exchange student. Ai Toyoshima, who arrived in this country just two months ago, died from a gunshot wound to the chest by an unidentified assailant. The wounded girl was found by a passer-by in a field behind an elementary school. Barely alive, Toyoshima was taken to a hospital, where before she died, she described her assailant to a police officer who speaks Japanese. She died at 6 a.m.