The jihadists are even attempting to sell the former criminal courts building in Gao, Mr. Sidibé said, because they no longer have any use for it. In Timbuktu, justice is dispensed from a room in a former hotel.

Many of the amputation victims have now drifted down to Bamako, in the south, which despite suffering from its own political volatility has become a haven for tens of thousands fleeing harsh conditions in the north, including the forced recruitment of child soldiers by the Islamists.

Moctar Touré, 25, and Souleymane Traoré, 25, both spoke haltingly and stared into the distance, remembering life before the moments that turned their worlds upside down and made them, as they felt, useless. They gently cradled the rounded stumps that now serve as arms, wondering what would come next.

The two young men had been truck drivers before Gao was overrun last spring. Both were accused of stealing guns; both said they merely acted out of patriotic feeling for the now-divided Malian state, with the intention of helping it regain the north.

In September, Mr. Traoré said, he was summoned from his jail cell after three months of a brutal prison term in which he was often fed nothing. Acquaintances had denounced him to the Islamist police; he was stealing the extremists’ weapons at night, he said, and burying them in the sand by the Niger River.

As ten other prisoners watched, he was ordered to sit in a chair, and his arms were tightly bound to it. With a razor, one of his jailers traced a circle on his forearm. “It pains me to even think about it,” he said, looking down, cradling his head in his remaining hand.