It is the deadliest attack by ISIS on the West in several years. But still, almost a week later, the group also known as Islamic State has yet to issue its trademark claim of responsibility for the horrific New Year’s violence in New Orleans.

Shamsud-Din Jabbar appears to have been inspired by the Islamic State, Biden says. The U.S.-designated terrorist group once controlled swaths of Syria and Iraq.

Recordings and interviews detail Shamsud-Din Jabbar’s growing discontent with American society and increasing isolation even within his local Muslim community.

A U.S. Army veteran from Texas who drove to Louisiana and deliberately plowed into New Year’s revelers in New Orleans recorded videos during the drive addressed to his family, in which he talked about plans to kill them and told them he had joined ISIS.

Since these people do not need to buy a weapon and can only rent a car, and take it to a populated place, the expert explained, it is easy to carry out such attacks.