So the man was a known criminal, had his asylum bid rejected (I think) and was under surveillance for possible links to terrorism yet was allowed to freely wander the streets in Germany. Then finally appeared two countries away. Not good.
Actually, reading the Italian press I think it is going to hit more hot buttons than "just"that.
At the moment reports are that
he came on a migrant boat to Lampedusa in 2011.
Knocked two years off his age and claimed to be an undocumented, unaccompanied minor.
Was convicted of being a principle in the burning down of a migrant holding centre.
Celebrated the Paris attacks in prison.
Served sentence.
We failed to deport him.
He used what was happening in Germany to try and claim asylum there.
It failed, but he didn't leave, or nobody made him leave. And he was flagged as a potential radical.
He committed mass murder.
Came back to Italy.
There's a lot in there that is going to leave a lot of people feeling TPTB have not laid a foundation that allows for reasonable checks and balances in terms of security.