1.   Several teams of disguised soldiers move across rooftops, through sewers, across dusty courtyards.

2.   One said they later found a few disguised North Korean soldiers among the dead.

3.   The AP also found once-classified documents showing that U.S. commanders ordered their troops to shoot civilians as a defense against disguised enemy soldiers.

4.   The ex-soldiers say they shot the civilians because they feared disguised North Korean soldiers were among the group.