German authorities would have immediately discounted his stopping drinking alcohol and starting to talk about the Qur’an as entirely irrelevant to whether or not he would mount a jihad attack. To have considered it as relevant would have been “Islamophobic.” Yet it actually is a reliable indicator: he became devout in Islam, and the Qur’an and Sunnah contain numerous exhortations to wage jihad against the Infidels.

“Hamburg stabbing suspect known as radical, mentally unstable,” by Geir Moulson, Associated Press, July 29, 2017 (thanks to The Religion of Peace):

BERLIN (AP) — A Palestinian man who allegedly stabbed one person to death and wounded six others in Hamburg was known to authorities as a suspected Islamic radical but is also psychologically unstable, German officials said Saturday.

The suspect, a 26-year-old who had no identity papers other than a birth certificate showing he was born in the United Arab Emirates, was quickly overwhelmed by passers-by and arrested after Friday’s attack at a supermarket in Hamburg’s Barmbek district.

He was not named by authorities in keeping with Germany privacy laws.

The man’s motive remained unclear Saturday but he is believed to have acted alone and there are no indications he had links to any network, Hamburg state interior minister Andy Grote said.

Police said the suspect grabbed a kitchen knife with a 20-centimeter (nearly 8-inch) blade from a supermarket shelf on Friday afternoon and stabbed three men, one of them fatally. He then left the supermarket and hurt another three people outside, not all of them with the knife. Passers-by then pursued and overwhelmed him and he was arrested by police….

The suspect arrived in Germany in March 2015 after stops in Spain, Sweden and Norway. His asylum request was rejected late last year and authorities were trying to secure new Palestinian papers to deport him — a process in which they said he had cooperated.

Officials said he was on their radar as a suspected Islamic radical but not as a “jihadist.”

A friend had tipped authorities off to changes in the man, telling them that he stopped drinking alcohol and started talking about the Quran, said Torsten Voss, head of the Hamburg branch of the domestic intelligence agency.

Officials interviewed him and came away with the impression he was a “destabilized personality” but not an immediate danger, Voss said.

“We evaluated him rather as someone who was psychologically unstable than had clear Islamic extremist motivations,” Voss said at a news conference. Authorities don’t know if he had any connections to Hamburg’s Islamic extremist scene….