to be killed&to have been killed

to be killed还没死没有被杀,将要被杀的意思,是一个将来时态.相当于will be killed
to have been killed 这个人已经被杀了,have been killed 是现在完成时表示已经完成的动作

to be killed carries the implication of "will",it means the man has not been killed.
however,"to have been killed"means the man is dead,he being no more.
got it?