Authorities in Tunisia on Saturday arrested three men suspected of connections to the truck attack at a Berlin Christmas market, including the nephew of the suspected attacker, CNN reported.
Authorities across Europe scrambled Thursday to track down a Tunisian man suspected of driving a truck into a Christmas market in Berlin, as one of his brothers urged him to surrender.
Communication was mainly conducted through the encrypted messaging app Telegram, and Amri asked his nephew to join the Islamic State in Iraq and Syria (ISIS) operating cell in Germany.
The three, aged between 18 and 27, have been in contact with Amri via social media, and also reportedly sent him money.
Despite an intense, Europe-wide manhunt, Amri was able to flee across Germany, into France and then into Italy, traveling at least part of the way by train, before he was shot early Friday in a police stop outside a deserted train station.
Italian authorities have not yet concluded whether Amri was acting alone or had accomplices.
"I did not notice anything unusual about him", she said, speaking to CNN exclusively from her family's home in the small Tunisian town of Oueslatia.
Protester Faten Mejri said "for us, they are not Tunisians".
Milan police said Amri had a few hundred euros on him but no telephone.
Nobody had alerted the police to Amri's presence in the city.
"He was a ghost", Milan police chief Antoio de Iesu said, adding that he was stopped because of basic police work, intensified surveillance "and a little luck".
Italy said it expelled a 37-year-old Tunisian who showed signs of radicalization while in jail, putting him on a flight to Tunis on Friday.
Without identification, Amri entered Italy in February 2011 and claimed to be a 17-year-old minor, a spokesman for the Italian state police, Mario Viola, told CNN earlier this week. "But the danger of terrorism as a whole remains, as it has for many years - we all know that".
Merkel said she had spoken to Tunisian President Beji Caid Essebsi about speeding up the process of returning Tunisians living in Germany illegally. He shot a senior officer in the shoulder before a rookie officer killed Amri with a single shot.
As Germany celebrated Christmas Eve meanwhile, locals and tourists in Berlin visited the Christmas market targeted in the truck assault, and many took a moment to quietly light a candle or lay flowers for the victims.
Authorities were also investigating the apparent coincidence that the truck from a Polish shipping company used in the Berlin attack had been loaded with machinery in the neighboring Milan suburb of Cinisello Balsamo three days before. He was not an extremist, he was like all young men around here.
They had been trying to deport him after his asylum application was rejected in July but were unable to do so because he lacked valid identity papers and Tunisia initially denied he was a citizen.