Yokohama's mayor said Wednesday she has instructed the city's board of education to investigate the reason behind its poor support in a case involving a 13-year-old boy from Fukushima Prefecture who had evacuated to the city in the wake of the March 2011 nuclear meltdowns and was bullied because he was from the radiation-devastated prefecture.

Mayor Fumiko Hayashi said in a press conference she ordered the board to look into the reason why it was so slow in launching its investigation into the case.

The board only started its investigation last December while the bullying started immediately after the boy moved to the city in August 2011 when he was a second-grader student.