Impuzamugambi
During the first few days of the genocide, the Rwandan Army and the Presidential Guard took charge of executing people in Kigali.  However, the Impuzamugambi and the Interahamwe were with them, and the soldiers taught them what to do.  Soon, they were working together.  First the soldiers would fire grenades, tear gas, and machine guns into places where Tutsis might be staying.  Then the militia were allowed to go in and kill everybody inside.  Often, they used machetes or clubs to kill people.  Then the soldiers and militia would search, inch by inch, to find anyone who might still be hiding.