As authorities investigate the motives for a mass killing in Nice late Thursday that was claimed by the Islamic State group, analysts say the case appears to highlight a shift in the profile of those launching attacks in the name of hard-line Islamist groups.

Mohamed Lahouaiej Bouhlel, who killed at least 84 people by driving a truck through crowds in the French seaside town, was not a pious, educated man in the mold of Mohamed Atta, one of the al-Qaida hijackers behind the Sept. 11 attacks in the United States in 2001.

Rather, neighbors and family describe him as a troubled man who lived apart from his wife and three children and drank alcohol, something forbidden by Islam.