The 30-year-old recounts how he was caught in the middle of the conflict between the Congolese armed forces (FARDC) and M23 rebels that has been raging since late 2021.
The attack on Kasereka took place at a coffee plantation in the agricultural town of Kibirizi in North Kivu province at the start of May.
It had been seized two months earlier by M23 and the Rwandan army, which has been fighting alongside the rebel group.
“When the M23 arrived in Kibirizi they held a meeting and assured us that we were safe,” Kasereka said, forlornly, in the hospital director’s office.
Instead, he said he was attacked by people “in M23 uniform”.
Bloodied and traumatised, he managed to climb a hill to safety in a government-held part of the town.
The Congolese army, backed by a rag-tag collection of armed groups known as Wazalendo, Swahili for Patriots, launched an offensive to retake Kibirizi from the M23 at the end of April.
Fighting raged in the centre of the town and FARDC mortar shells destroyed houses and killed those living there, a Congolese army colonel acknowledged. “Collateral damage,” he said.
But the army failed to retake Kibirizi, leaving its inhabitants at the mercy of the M23 who began to “attack the population” when the Congolese army left, Kasereka said.
The men who cut Kasereka’s neck, and sliced the throat of his friend Germain, who died, accused them of belonging to a group of militia who had ambushed them.
“They suspected us of being traitors and of having facilitated the entry of the Wazalendo into the town,” Kasereka said.
In 2022, more than 100 people were killed for the same reason in Kishishe, a town some 10km (6 miles) from Kibirizi.
The United Nations later found that M23 was responsible for the massacre.
Kasereka has been recovering for about 10 days at a hospital in the town of Kanyabayonga, about 10km from where he was attacked.
In the bed next to him, an 18-year-old fighter, also named Germain, lies in dirty bedsheets with bandages around his wounded arm.
Germain has been fighting for four years with the FPP/AP (Front of Patriots for Peace/People’s Army), one of the largest armed groups in the area that is part of the Wazalendo.
But he was wounded by rocket shrapnel during the failed bid by the Congolese army and its allies to regain control of Kibirizi.
For almost two years, the FARDC and Wazalendo have not seen a single victory, as M23 continues its advance in North Kivu province.
Augustin Darwin, FPP/AP spokesman, said he had no confidence in the FARDC as it failed to respect agreements with armed groups.
He accused the Congolese army of “withdrawal after withdrawal” and “fleeing before the enemy”.
His soldiers have “no boots, no uniforms [and] do not receive rations”, Darwin said from the group’s headquarters in Mbavinwa, a small village about 10km from Kanyabayonga.
“They are demoralised,” he added.
If there were less embezzlement in the army, “the FARDC wouldn’t even need the Wazalendo”, he said.
Kanyabayonga has become a refuge for tens of thousands of displaced people who have fled the fighting and abuse by M23 rebels.
But the town’s mayor, Chrisostome Kasereka, worries the area could be bombed. “We are living in fear,” he said.
In recent weeks, three mortar shells have fallen around Kanyabayonga, the mayor said, as his secretary showed the remnants of a projectile missile found in a field.
Civil society leaders from Kibirizi, Kanyabayonga and Kishishe also say certain FARDC officers have “facilitated passage to the rebels”.
The FARDC officers were summoned to the capital, Kinshasa, as part of an inquiry in mid-March, but some of them have already returned to Kanyabayonga.
“Impunity is what makes things not work in our Republic,” Kasereka despaired.
Congolese armed forces and Wazalendo fighters have launched a new offensive in Kibirizi.
“Every day, trucks full of soldiers arrive here,” one of the town’s civil society leaders said.
“If they [the FARDC soldiers] do the ‘strategic withdrawal’ thing again, we will see a fight between the Wazalendo and the FARDC … and we ourselves will take up arms,” he warned.