Who was Copenhagen gunman Omar Abdel Hamid El-Hussein?

So said Aydin Soei, an author and sociologist who met Omar Abdel Hamid El-Hussein as a troubled teenager in 2011.

Police have still not formally named El-Hussein as the suspect in the shootings at a Copenhagen cafe and outside a synagogue. His identity was confirmed by a senior member of the Danish government, however.

The Danish-born 22-year-old, reportedly of Arab origins, was killed in a shootout with police.

Authorities said he was “well-known by the police for several criminal incidents,” including weapons violations and violence, and that he was “known in connection to gangs.”

But questions remain over who he was, how he became radicalized and whether the threat he posed could have been spotted before the deadly attacks.

El-Hussein’s path to radicalization — and what propelled him to act — will now be under scrutiny.

Authorities are “operating under a theory” that the gunman may have been inspired by the January terror attacks in France, said Jens Madsen, the agency’s chief.

Seventeen people died in the Paris attacks, which targeted the offices of satirical magazine Charlie Hebdo, which had published cartoons of the Prophet Mohammed, and a Jewish supermarket. Two of the gunmen were linked to Yemen’s al Qaeda affiliate, while a third — supermarket attacker Amedy Coulibaly — pledged allegiance to al-Baghdadi in a video he emailed out before the assault.

The similarities with the Copenhagen attack, in which El-Hussein also targeted a cartoonist who’d depicted Mohammed as well targeting members of the Jewish community, are chilling.

CNN’s Nic Robertson reported from Copenhagen and Laura Smith-Spark wrote from London. CNN’s Ali Younes and Susanne Gargiulo contributed to this report.

CNN