Fofana was the leader of a group of African Muslim immigrants known as the Gang of Barbarians. The Gang adhered to Anti-Semetic views, believing all Jews to be rich from cheating, and as such decided to target Jewish families for ransom money.
On 20 January 2006, one of the gang's members approached Ilan Halimi and asked for his number. The next day she called him and asked him to come to her apartment. Upon arriving he was set upon, bound and gagged by Fofana and the rest of the gang. The day after that the gang sent Halimi's family a photo of him with a message demanding 450, 000 euros for his release. As the Halimi family did not in fact have that much money all they could do was contact the police and report a kidnapping.
Every day the money didn't arrive Fofana and the Barbarians sent Halimi's family footage of him being tortured. At one point during the police investigation Fofana was arrested, but he was released due to a lack of evidence. Eventually, after 24 days of captivity, the gang accepted they weren't going to get a ransom and dumped Halimi at the side of the road. A passer-by found him and called an ambulance, but Halimi died on the way to the hospital.
After a facial composite was released of the woman who lured Halimi, another woman associated with the gang turned herself in to police. She pointed them to Fofana and his gang, and a warrant was released for Fofana's arrest. Fofana fled back to his home in Côte d'Ivoire, where he was arrested and extradited to France.
Fofana and 26 others allegedly involved in the kidnapping were charged with kidnapping and murder. Fofana was also charged with extortion after being implicated in various extortion cases in which he messaged several high-profile CEOs claiming to be from the National Front for the Liberation of Corsica or the Popular Front for the Liberation of Palestine and threatened to kill them unless they payed him 100, 000 euros.
During the trial Fofana largely remained silent. However, when asked his date of birth he replied "My name is arab, armed african rebellion, salafist barbarian army and I was born on February 13, 2006 in Sainte-Geneviève-des-Bois" (the latter part being the date and location where Ilan Halimi was found). He also had to be restrained after throwing a shoe and claiming it was a bomb, and threatened to have his friends go after the jurors. He was eventually convicted and sentenced to life imprisonment. He received an additional 10 years in 2017 for his extortion plots.