A soldier stands beside a house burnt during the clash between Islamist insurgents and soldiers in Baga. Photograph: Pius Utomi Ekpei/AFP/Getty Images
The road to Baga is littered with burned-out cars, winding through terrain that has proved fertile ground for radical ideologies to take root. On the cusp of the Sahara, it traces a route through the former ancient Islamic kingdom of Bornu, a thriving sultanate that grew rich on trans-desert trade. Now known as Borno state, today it is home to some of Africa's most impoverished communities.
Boko Haram, Islamist insurgents whose bombs are responsible for the carcasses of cars on the roadside, have thrived by tapping into a yearning for ancient glory amid crippling poverty.
Now the residents of Baga, a remote fishing settlement on the shores of Lake Chad, have a new reason to be angry. Last month the village was the scene of one of Nigeria's most deadly incidents since the Islamist insurgency began in 2009, with locals saying 185 of their kin died, most of them civilians and most of them burned to death. That figure has been disputed by the military, who told the Guardian that only 37 people were killed, most of whom were Boko Haram fighters. The Guardian was the first international newspaper to gain access to Baga since the killings.
The afternoon before it happened, Ali, a white-haired village chief, overheard a conversation that turned his stomach. Just outside his mud-walled home, two men in military uniforms were talking heatedly: one wanted to set fire to Ali's neighbour's house; the other was trying to stop him. That morning a Nigerian corporal, known as Kia, had been killed after being ambushed by fighters from Boko Haram.
"One of the men said, 'we must avenge his death, we must set a house on fire'; the other one said no, he wanted no part of this," Ali said, sitting on an orange raffia straw mat at a meeting convened by village elders.
"After that," he continued "I don't know what happened." Ali looked nervously at the dozens of men in flowing robes packed under the thatched-roof shelter for the meeting, many of them young and unemployed, a key source of support for Boko Haram.
When the morning of 17 April dawned, much of this fishing village was a smouldering wreck. Black carcasses of houses and skeletal trees stood out starkly against the expanse of fine pale sand. The devastation wrought here highlights how Boko Haram is turning to cross-border raids with deadly consequences.
Members of the violent jihadist movement have infiltrated this town along the dozens of sandy footpaths leading to their hideouts across the Sahara desert. Their attack on the Nigerian corporal, using a sophisticated rocket-propelled grenade (RPG), was so violent that Kia's head had to be sewn back on before his body could be returned to his family for burial, officials said.
After the decapitation, the insurgents fled deep into the desert, another Baga village elder said, leaving the civilian population to face the wrath of the army. The military denies that, saying the militants were hiding in Baga and were extremely well armed.
"There was a firefight, which lasted four hours after reinforcements were brought in. The terrorists used IEDs [improvised explosive devices] and rocket-propelled grenades, which caused the thatch-roof houses to catch fire," Brigadier General Austin Edokpaye, head of the Joint Task Force stationed in Baga, told a delegation of senators investigating the incident this week.
Tellingly, the mission stationed in Baga includes soldiers from Niger and Chad, as west African forces increasingly share concerns about growing links between jihadist groups.
Outside the bleak Baga military outpost, Edokpaye showed an array of weapons, including sophisticated machine guns and RPGs, which he said had been captured from the fighters. "When you hear the sound of some of these weapons – these were not any weapons from Nigeria," he said.
Amid the swirling accusations and counter-accusations, the incident has thrown the spotlight on to the Nigerian military's often brutal tactics in its fight to root out an enemy that easily dissolves into the civilian population, many of whom support Boko Haram out of fear as much as out of hatred of the security forces.
Bolstered by arms from Libya and Mali, Boko Haram appears to be able to penetrate vulnerable outposts along Nigeria's porous borders before retreating into the vast Sahara. Officials and residents in both Nigeria and Mali said members of the group had trained in Mali after a coup threw the country into disarray last year.
"The last Boko Haram member we captured here was about two weeks ago. He had boarded a bus to [Mali's capital] Bamako, he was carrying a lot of cash, a lot of weapons," a Malian security official in the town of Gao said.
With hundreds of unguarded footpaths leading to neighbouring Chad, Niger and Cameroon, parts of Nigeria's remote Borno and Yobe states have been all but taken over by the shadowy sect. A French family taken hostage in Cameroon were held undetected for two months in a town less than 20 miles from Baga, Cameroonian and Nigerian security officials said.
On Tuesday, Boko Haram members staged an audacious raid in Borno state, mounting a co-ordinated attack against a prison and army barracks in the town of Bama that left 47 dead and freed more than 100 prisoners. "They used lorries mounted with anti-aircraft guns," a senior security official said. "These are weapons from Libya." The attack prompted Nigeria's president, Goodluck Jonathan, to cut short a trip to Namibia.
Kashim Shettima, governor of Borno state, said poverty was at the root of the problem. "Unless, and until, we address some of these fundamental issues [of poverty], believe me, the future is very bleak for all of us," he said.
Mohammed, an unemployed youth languishing on his bike, explained the militants' appeal. "If a man gives me 20,000 naira [£80] today, then I will work with him for life. That is what I hear Boko Haram are doing. What else is there for us to earn money here?"
Beyond the remains of camels half-sunk into the sandy roadside, turbaned men on horses ride past children sitting under neem trees with chalkboards. Almajiri, or Qur'anic schools, flourish here, in stark contrast to weed-covered signposts marking the entrance to abandoned government schools.
In Baga, every government school has been shut since August 2012, when leaflets appeared on school walls threatening to kill anyone attending, residents said.
But in trying to root out Boko Haram, which means "western education is forbidden", from a population trapped in the middle, the human cost has been unbearably high to many. In Usman's mud home, jewel-coloured cloths had been bought and mounds of fish smoked to prepare for his daughter's wedding.
Instead, on the big day, his household was muted with grief as they mourned the loss of 13 family members killed in the town. "I wonder what we have done wrong in Allah's eyes for this to happen," the grandfather said, crying softly.
Senator Abdul Ahmed Ningi, speaking during the government delegation's visit to the town, said: "Not every soldier is an enemy to the people here. That's exactly why the person responsible [for the Baga killings] must be bought to book. Unless the Nigerian military can start winning hearts and minds, the situation is going to become even worse."
Civilians caught in the crossfire can only hope for better days. "Imagine it is night, we are inside our homes, then suddenly our homes were on fire," said one villager in Baga, standing in front of his charred mud home. Looking over to the bright green grasses on the shores of Lake Chad in the distance, he added: "We are simple fishermen here. We just want peace."