BBC Chinese, Feb. 6, 2010.
http://www.bbc.co.uk/zhongwen/simp/china/2010/02/100206_731doc.shtml
My comment:
(a) 日本发现美军下令检查731部队相关人员信件的档案. Kyodo, Feb. 6, 2010.
http://china.kyodo.co.jp/modules/fsStory/index.php?sel_lang=schinese&storyid=78115
I cannot find a corresponding English report.
(b) This is the only English-language report from Japan that I can find.
U.S. forces ordered all mail items sent to ex-Unit 731 members to be
censored. Mainichi Shimbun, Feb. 6, 2010.
http://mdn.mainichi.jp/mdnnews/news/20100206p2a00m0na002000c.html