“Doundoun is a terrorist, who is recognized as a leader of the group who conducts operations in the border area,” said Niger’s minister of defense, Kalla Moutari. “We had intelligence confirming the presence of this terrorist,” he added, noting that, “on the basis of this information, action was taken.”

“Military officials quickly ordered up an assault team of American, French and Nigerien commandos based in Arlit, 700 miles northeast of the capital, to go after Mr. Cheffou, officials say — part of a broader counter-terrorism mission named Obsidian Nomad.”

“The Nigerien forces at Arlit were specially trained and equipped by the Pentagon for counterterrorism operations like this one. They were accompanied by American Special Forces advisers who had arrived in the country roughly a month before, officials say.”

“It is not clear how many Americans and Nigeriens were assigned to the helicopter assault mission, or who approved the operation. Such raids have been conducted in Somalia, but the tactic was unusual for the American military in West Africa. Senior American officers who have served in West Africa say it probably would have required Gen. Thomas D. Waldhauser, the head of the military’s Africa Command, in Stuttgart, Germany, to approve such a high-level mission.”

The scramble to pull together a raid and hunt down Mr. Cheffou upended what had been a fairly uneventful day for the four American sergeants already out on patrol.

They were part of a group of 11 American and 30 Nigerien soldiers with a very different assignment: to visit a number of villages to meet with residents and leaders. It was considered routine, low risk and something they were well equipped for.

Their convoy was composed of eight vehicles: two pickup trucks and a sport utility vehicle for the Americans, and five trucks for the Nigeriens. Most had medium machine guns, capable of being fired by standing and aiming from the bed of the truck. The unit’s vehicles, the only ones assigned for the deployment, were lightly protected but relatively low profile. They could quickly travel overland on missions that were less dangerous than those in Iraq and Afghanistan.”

Their weapons were similarly configured. The Americans in the group — an Army Special Forces team called Operational Detachment-Alpha Team 3212 — had been operating in Niger for a little over a month. Most of the team carried M4 carbines, with sights and suppressors for their rifles, according to the video footage. At least one soldier had a single-shot grenade launcher.

For visiting local villages in an area that was supposed to have little militant presence, the team’s weapons and vehicles made sense. But if attacked by a larger, more aggressive force, Team 3212’s members would barely have enough rifles and machine guns to defend themselves.

And their trucks, lightly protected with open beds, would leave any passengers inside exposed to enemy fire. Soldiers traveling in the lone S.U.V. could also wind up dangerously confined — with little ability to shoot back — inside the vehicle.

“Starting around 6 a.m. on Oct. 3, the Americans and their Nigerien counterparts headed out from their base in Ouallam, 60 miles north of Niamey, to villages to meet with community leaders, according to two of the Nigerien soldiers on the mission. In the afternoon, their assignment completed, they began to head back to base.”

“Before they got there, a new order came in: provide backup to the assault mission gearing up in Arlit. The plan was not for Team 3212 to join the raid, officials say, but to get close enough to pursue escaping militants or help out as needed.”

“So, without warning, the Army soldiers out on a daylong patrol with their Nigerien trainees were turned around, pushing deeper into potentially hostile territory, lightly equipped for a new mission that exposed them to risks their commanders did not anticipate.”

“It is not clear who gave the order for Team 3212’s new mission. Officers who have served in the region say such a change would require approval and tasking from at least several higher levels — most likely starting with a major in Niamey and a lieutenant colonel in Chad; a task force commander stationed in Germany; and possibly a two-star general overseeing all special forces operations in Africa, also from Germany, where the US Africa Command is based.”

“But soon, the plans changed yet again. Back in Arlit, the preparations for the raid were falling apart. Bad weather or mechanical problems scotched the assault team’s helicopter mission, and American spy agencies determined that Mr. Cheffou and a handful of fighters had left the location, officials say. They believed the trail had gone cold.”

“Still, Team 3212 and the 30 Nigeriens with it were moving into position to back up a raid that was no longer happening, officials said. The same chain of command ordered the team to press on — now on its third assignment in 24 hours. Could the team salvage some of the mission by searching the site where Mr. Cheffou had been, collecting any scraps of information left behind that might offer clues about his hide-outs and network?”

“By this point, current and former military officers and counterterrorism specialists say the team and its chain of command had made some crucial mistakes that would come back to haunt the soldiers.”

“First, the superiors who redirected Team 3212 failed to take note of the increasingly hazardous environment in the border area between Mali and Niger — an area where the United Nations had counted at least 46 attacks in the 20 months before the ambush.”

“But the American Special Forces had faced virtually no enemy contact during months of patrols in the region, Pentagon officials said. The Nigerien troops who set out alongside the Americans had been to the area where the ambush occurred a total of 19 times without incident, said Brig. Gen. Mahamadou Abou Tarka, a senior Nigerien officer.”

“This led to a general complacency, and a false sense of safety, which took root both in the rank-and-file members of the unit and in their commanders, American and Nigerien officials said. Although the Americans in Team 3212 were well trained, they were new to Niger, and some of the soldiers were on their first tour. They were accompanied by Nigerien troops, who are classified as special forces but are, in fact, their trainees.”

“The sense of urgency and risk that infused the planning around the raid from Arlit seemed to recede once that mission was scrubbed and Mr. Cheffou vanished — even though he and his fighters may have remained in the area Team 3212 was entering.”

“As the team pushed on toward the location, running on a set of plans hastily put together, the air support assigned to the raid dropped off. French forces that had been alerted to stand by to support the impending operation also stood down. The team, assigned to support a priority mission, was on its own, current and former American military officials say.”

“Raids are typically carried out between the hours of midnight and 5 a.m., when darkness allows troops to take advantage of one of the tools Americans have at their disposal: Night-vision devices.”

“Even though the mission was scrubbed, Team 3212 apparently stuck to the same schedule. The Americans and Nigeriens bedded down in sleeping bags next to their vehicles, according to one of the Nigerien soldiers. They rose while it was still dark and pushed through to the militant campsite, hidden under a canopy of trees and set back in the rocks just shy of the Mali border.”

“It was empty, the 2 Nigerien soldiers said. But someone had been there recently: They found tea, sugar and flour, and an abandoned motorcycle. The tracks in the sand indicated that other motorcycles had sped away. They also found signs of weapons, including 14.5-mm rounds that are fired by antiaircraft weapons capable of heavily damaging most lightly armored vehicles. A case of 12.7-mm heavy machine gun bullets was also found, one Nigerien soldier said.”

“The team gathered material from the campsite and began the long drive back to base as the sun was rising. They had traveled no more than 20 miles of the approximately 110-mile journey back when they approached the first village on their route, a speck on the map known as Tongo Tongo.”

“They were tired and out of water, said one of the Nigerien soldiers who survived. They decided to take a break just outside the village, near a well. A group of villagers approached them, and one offered to run to the village to get them the bucket. He returned sometime later, and they filled their bottles with water.”

“It is unclear who approved the pit stop. But whatever the reason, the delay — in a location close to Mr. Cheffou’s campsite — made the team more vulnerable with each passing moment in unfamiliar territory. The team had been out for more than a day, pushing through the desert in easy-to-spot vehicles, giving the militants and their web of spotters time to plan an ambush.”

“The village chief walked out to meet the convoy, explaining that several children were sick. The unit began distributing medicine, the Nigerien soldiers said. Some of the soldiers saw men speeding out of the village on motorbikes, they said, possibly to alert the militants.”

“How did the terrorists know that the white people were in our village giving out medicine?” said Boubacar Hassane, 45, a villager who was hoeing his millet field outside of the village that day.

“Some soldiers had the impression that the chief was trying to delay them. He was later arrested, and his phone contained the numbers for known terrorists, including one connected to Mr. Cheffou, Nigerien officials said.”

“Around 11:30 a.m., the patrol left for home. But right outside the village, the convoy came under attack from militants with small arms, machine guns and rocket-propelled grenades”.

“Early in the firefight, Team 3212’s leader, Capt. Michael Perozeni, and a radio operator, Sgt. First Class Brent Bartels, were both shot and wounded, probably reducing the team’s ability to communicate to higher command, a military official said.”

“In the first radio transmission, the Americans said that Team 3212 was in enemy contact, according to military officials. But they did not call for help for another hour. It’s unclear why. For troops in Niger, radio communications are often plagued by distance and terrain. Whatever the reason, the team was unable to talk with French air support and had to communicate through officers in Niamey, according to a draft report of the investigation.”

At some point, the convoy split up, leaving at least two of the vehicles cut off under heavy gunfire. Sgt. Jeremiah Johnson, Sergeant Wright and Sergeant Black were in the black S.U.V.

Somehow, it was left behind.

Roughly 2 hours after the ambush began, the first sign of air support arrived. French Mirage jets flew in low and fast. Behind them came French helicopters with American Special Forces stationed in Mali. The helicopters evacuated the American wounded and the other members of the team who made it to the landing zone.

The Pentagon has long asserted that the Americans killed were not left behind, and that teams of Nigerien and French forces were in the area immediately, looking for them.

The video of the ambush suggests otherwise. At least 2 of the dead American soldiers were shown stripped of their equipment and photographed by the Islamic State militants at close range. For a period of time, American troops were in the hands of their enemy.

That night, the American Special Forces unit from Arlit arrived in helicopters run by a civilian contracting company and recovered the bodies of Sergeant Wright, Sergeant Black and Sgt. Jeremiah Johnson.

It wasn’t until Oct. 6 that locals found the body of Sgt. La David Johnson.

Link: ‘An Endless War’: Why 4 US Soldiers Died in a Remote African Desert