As investigators learn more about the man who pledged allegiance to the Islamic State (IS) group and killed 14 people with a truck on New Year¡¯s Day in New Orleans, a key question remains: How did a veteran and one-time employee of a major corporation become radicalized?

FBI Deputy Assistant Director Christopher Raia said on Thursday that videos made by Shamsud-Din Jabbar just before the attack showed the 42-year-old Texas native supported IS, claimed to have joined the militant group before last summer and believed in a ¡°war between the believers and nonbelievers.¡±

While the FBI was looking into his ¡°path to radicalization,¡± evidence collected since the attack showed that Jabbar was ¡°100% inspired by ISIS,¡± said Raia, using an acronym for the Islamic State group.