sentences:  About a month before Minh's junta was overthrown, Khánh was approached by one of the principal tacticians in the removal of Diệm, General Đỗ Mậu.A colonel at the time of the previous coup, Mậu had been head of military security under Diệm.Although he did not explicitly command troops, Mậu had a thorough knowledge of the backgrounds of most of the senior ARVN officers and their strengths and weaknesses.