What the media have been reporting over here about the suspect via family and people that know him, it's a bit of a weird mix up of a very mentally unstable person. He's described as a renowned drug dealer who switched up phases of maniacal alcohol and cocaine use with months of sobriety where he dressed and acted like a very devout muslim.
Long criminal record and record of mental instability, cases of attempted manslaughter, drug dealing, robberies and firearms related. Attempted suicide once by jumping from a three story building. His brother is known by the authorities for flirting with extremistic branches of Islam, some of his other family are described as deeply religious, which is where the terrorism angle came in.
Two weeks ago the preliminary/research phase of a trial started against him, for raping and assaulting his former girlfriend back in 2017, which is now speculated to be the thing that pushed him over the edge.