The brother of the terrorist who killed 15 people and injured more than 30 others in New Orleans claims his sibling was radicalized.

Abdur Jabbar, 24, told the New York Times that his brother, Shamsud-Din Jabbar, 42, a Texas native and U.S. Army veteran, converted to Islam at an early age, but his brother's rampage "does not represent" the religion, rather "some type of radicalization." The elder Jabbar reportedly pledged his allegiances to the terrorist group ISIS and planned to kill his family prior to the attack, multiple officials briefed on the investigation confirmed to CNN.

The Army veteran referenced his divorce and plans to gather his family for a "celebration" with the intention to murder them, but said he changed his plans and joined ISIS in video recordings suspected to be made while driving to Louisiana to commit the attack. The recordings appear to have been made at night, however, the exact timing is unclear, according to officials.

Jabbar was killed during a shootout with police after plowing a rented truck through a crowd of people during the New Year's Day celebration in the French Quarter. The suspect was found to have possible improvised explosive devices and an ISIS flag attached to his truck at the time of the incident, according to local and federal authorities.

President Joe Biden said that the FBI notified him that Jabbar "posted videos on social media indicating that he's inspired by ISIS" and expressed "a desire to kill" a "mere hours before the attack" via ABC News. Two officers were reportedly shot during the incident but listed to be in stable condition.