A routine request for ID papers outside a deserted railway station in a Milan suburb at 3am led to a police shootout that killed the Tunisian fugitive wanted in the deadly Christmas market attack in Berlin.
While authorities expressed relief that the search for Anis Amri was over, his four-day run raised fresh questions about whether he had any accomplices, and how Europe can stop extremists from moving freely across its open borders, even amid an intense manhunt.
Italian police said Amri travelled from Germany through France and into Italy after Monday night's truck rampage in Berlin, and at least some of his journey was by rail.
Italian prime minister Paolo Gentiloni called for greater cross-border police co-operation, suggesting some dismay that Europe's open frontier policy had enabled Amri to move around easily despite being its No 1 fugitive.
Amri, whose fingerprints and wallet were found in the truck that ploughed into Christmas markets outside Berlin's Kaiser Wilhelm Memorial Church, killing 12 people and injuring 56 others, was caught seemingly by chance after eluding police for more than three days.
"He was a ghost," Milan police chief Antoio de Iesu said, adding that Amri was stopped because of basic police work, intensified surveillance "and a little luck".
Italian officials stressed that the two young officers who stopped Amri didn't suspect he was the Berlin attacker, but rather grew suspicious because he was a North African man, alone outside a deserted railway station in the dead of night.
Amri, who had spent time in prison in Italy, was confronted by the police in Sesto San Giovanni, a suburb of Milan. He pulled a gun from his backpack after being asked to show his ID and was killed in an ensuing shootout.
One of the officers, Christian Movio, 35, was shot in the right shoulder and had surgery for what doctors said was a superficial wound. His 29-year-old partner, Luca Scata, fatally shot Amri in the chest.
The Islamic State group has claimed responsibility for Monday's attack. On Friday, it noted his death in Milan and released a separate video showing Amri swearing allegiance to the group's leader, Abu Bakr al-Baghdadi, while vowing to fight non-Muslims.
German authorities were suspicious of Amri and had put him under covert surveillance for six months after a warning from intelligence agencies that he might be planning an attack. But the surveillance ended in September after police found no proof of his alleged plans.
Separately, German authorities tried to deport Amri after his asylum application was rejected in July but were unable to do so because he lacked valid identity papers, and Tunisia initially denied that he was a citizen. Authorities said he has used at least six different names and three nationalities.
Family members in Amri's central Tunisian hometown of Oueslatia said he wasn't particularly religious before leaving for Europe after the 2011 Arab Spring.
After learning of his death, Amri's mother said she feared the world would never know why he allegedly rammed a truck through a holiday crowd.
"Within him is a great secret. They killed him, and buried the secret with him," Nour El Houda Hassani told The Associated Press. She begged for his remains to be brought home, and said, "I want the truth about my son - who was behind him, those who indoctrinated him."
