They were looking for new ways to kill, ways to send fresh terror across North Kivu.
It was early afternoon when the M23 militia raided the Congolese town of Rubaya. In a marketplace, gunmen found a giant wooden pestle and mortar for crushing grain. They began rounding up children, wedging them tight in the mortar. Isabel, 32, watched the rebels stove in their skulls. The mortar turned red, overflowing with blood.