Eugène Bonnier was described as "Brown hair, high forehead, strong nose, dark chestnut eyes, small mouth, round chin, oval face, 171 centimetres (67 in)".

[4] When the civilian governor Albert Grodet reached Sudan Eugène Bonnier had left on an expedition against Timbuktu despite strict instructions by the government to the contrary.

The same day Bonnier left Ségou 350 miles (560 km) to the east on the Niger River bound for Timbuktu, which he expected to take without difficulty.

[7] Bonnier was followed two days later by Major Joseph Joffre with a force of 400 infantry and cavalry, 700 porters, 200 mules and a battery of field artillery.

[4] Bonnier reached Mopti after four days, and found that rather than wait there as ordered, Boiteux had continued with the gunboats to Kabara, the port for Timbuktu.

In a heated interview he accused Boiteux of having left the main party that he should have been protecting, and of having then abandoned his boats with the loss of 17 men, so he could be the first to reach Timbuktu.

Bonnier confined Boiteux to quarters for thirty days, a lenient sentence but typical of colonial Africa of the time when all the soldiers were scrambling to obtain glory.

The animals stampeded and the Tuareg broke through the thorns and killed Bonnier and 11 other officers, two NGOs, a native interpreter and 68 tirailleurs.

[14] However, after the disappearance in 1896 of the desert expedition organized by the marquis de Morès there were growing demands to inflict punishment on the Tuaregs.