Hunting Boko Haram

A convoy of Chadian soldiers passes by a signboard painted by Boko Haram in the recently retaken town of Damasak, Nigeria, March 18, 2015. Armies from Nigeria, Cameroon, Chad and Niger have launched an offensive to end Boko Haram's six-year campaign, which has killed thousands in northern Nigeria and spilled over into Cameroon and Niger. REUTERS/Emmanuel Braun

Chadian soldiers hold weapons in the recently retaken town of Damasak, Nigeria, March 18, 2015. REUTERS/Emmanuel Braun

Chadian soldiers drive in the recently retaken town of Damasak, Nigeria, March 18, 2015. REUTERS/Emmanuel Braun

A flag belonging to Boko Haram flies from a atop a mosque in the recently retaken town of Damasak, Nigeria, March 18, 2015. REUTERS/Emmanuel Braun

Chadian soldiers carry weapons captured from Boko Haram in a pickup truck in the recently retaken town of Damasak, Nigeria, March 18, 2015. REUTERS/Emmanuel Braun

Chadian soldiers walk in front of a building that Boko Haram insurgents used as their base before being driven out by the Chadian military in Dikwa, Nigeria, March 2, 2015. REUTERS/Madjiasra Nako

Debris is scattered in front of a building that Boko Haram insurgents used as their base before being driven out by the Chadian military in Dikwa, Nigeria, March 2, 2015. REUTERS/Madjiasra Nako

Chadian soldiers drive past the body of what they said was a Boko Haram fighter they killed in battle in Dikwa, Nigeria, March 2, 2015. REUTERS/Madjiasra Nako

A Chadian soldier walks past an armored vehicle that the Chadian military said belonged to insurgent group Boko Haram that they destroyed in battle in Gambaru, Nigeria, February 26, 2015. The Chadian military said that Boko Haram had taken the vehicle from the Nigerian military. REUTERS/Emmanuel Braun

A Chadian soldier rides atop a pickup truck next to a bag of rocket-propelled grenades in Gambaru, Nigeria, February 26, 2015. REUTERS/Emmanuel Braun

A Chadian soldier wears charms for protection near the front line during battle against insurgent group Boko Haram in Gambaru, February 26, 2015. REUTERS/Emmanuel Braun

Chadian soldiers stand next to what they say was a camp for insurgent group Boko Haram, which the Chadian military said they destroyed in battle, in Gambaru, Nigeria, February 26, 2015. REUTERS/Emmanuel Braun

Chadian soldiers drive past the body of a man they say was a Boko Haram fighter the Chadian military killed in battle in Gambaru, Nigeria, February 26, 2015. REUTERS/Emmanuel Braun