What is official is the following.
Danish born, 22 years old, connected with gangs and has a history of violence. Just got out of jail 2 weeks ago for assault and well known by the Danish Police.
As of now, no known links to any radical Islamist groups or travel outside of Denmark to "those areas". Has spent the last few years in and out of jail.
As of now it looks like this guy had more in common with the Hells Angels, Russian mob, Crips and Blood and all those other organized gangs than ISIS. But it is early in the investigation, so we shall see.. but he was only 22 and spent most of his early adult life in jail, so..