"We are studying all possible connections (between Amri) and our country, above all with one specific person," Interior Minister Juan Ignacio Zoido told Spanish radio. Italy has found itself at the center of the Berlin attack investigation after the dramatic shootout early Friday that ended the manhunt. The deserted train station and the late hour prompted Italian officers to check the North African man's identity, officials said. Instead of pulling out an identity card, Amri produced a loaded .22 caliber gun, shooting a senior officer in the shoulder before a rookie officer killed him with a single shot. Amri had arrived in the southern island of Lampedusa illegally in 2011, claiming to be a minor, and quickly landed in jail after setting fire to a migrant center. After he was freed, efforts to deport him failed for bureaucratic reasons. He reached Germany, where authorities were concerned enough to put him under covert surveillance for six months earlier this year, ending the operation in September. His request for asylum was refused by Germany in the summer, but the paperwork from Tunisia needed to deport him was delayed for months. Investigators are looking into why Amri returned to Italy this week as he sought to elude police and whether he had any jihadi contacts in the country. 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 the attack. Milan Police Chief Antonio de Iesu acknowledged the connection was "suggestive." But he told reporters there was no evidence yet of a link, emphasizing that the Polish truck driver who was the terrorist's first victim had spoken to his wife by phone from Berlin hours before the attack and did not appear to be under duress.