Elementary school student Jian Macdonald had always thought policemen were cool — especially ones that rode fast motorcycles.

In September last year, Jian was riding through Ueno on the back on his father's motorbike when they spotted a traffic cop at the side of the road. They pulled over and chatted with the officer, who was kind enough to let Jian sit on his motorcycle and pose for a photograph.

But the following month something happened that would forever taint the 8-year-old's image of the Japanese police.