reporter: in 2008 six children died and an estimated 300,000 fell sick after drinking contaminated with melonine. questions are asked as to how the over sight could have happened. >> translation: there are supposed to be regulations and supervision of vaccine production and use. why was there a lack of supervision? sometimes laws and rules are not supervised enough >> reporter: over the past week police have arrested more than 100 people and are investigating dozens of pharmaceutical companies, but parents like lee want to sew more accountability. >> translation: the government supervisors should be held responsible, not just the mother and daughter who have been sending the vaccine. >> reporter: many blame the government for releasing news about this nearly a year after the first suspects were arrested last april >>> finally, the cherry blossoms which draw thousands of visitors to washington every year are out in full bloom. >> reporter: for a week or two each year washington dc is transformed. its cherry blossom time. the legacy of a gift of trees from japan to the u.s. in 1912. metropolitan t