from wiki:
http://en.wikipedia.org/wiki/Mississippi_civil_rights_workers_murders
The Mississippi civil rights workers murders involved the 1964 lynching of three political activists during the American Civil Rights Movement.
另外manslaughter不是誤殺,而是殺,誤殺是involuntary manslaughter。俺英語不好啊,不過這個還是肯定地。