I could have no such evidence as I have no access to the culprit’s mental assessment file.
But just in last 2 months, we have seen about 5-6 cases of violence by Immigrants which are swept away as mental illness.
I find it difficult to digest that all mentally ill would act one by one, and only be violent towards residents of that country, not towards fellow Immigrants .
These violent acts plus the Cologne rape molestation case few months ago, do indicate that there is some sort of cultural shock & few are unable to cope.
With enough cultural grooming, sanest of all could do violent acts.
Just like Homophobia where good people are dismissive of gays & violent towards them.