Authorities in Germany have detained a man for questioning in connection to the deadly attack on a Christmas market in Berlin earlier this month.Last week, police in Milan, Italy, shot and killed Anis Amri, the Tunisian man suspected of driving a truck into the market on Dec. 19. Twelve people died in that attack.Now they are questioning a 40-year-old man whose phone number was found in Amri's cellphone."This new suspect is also from Tunisia and police say investigations indicate he may have been involved in the attack," Kerry Skyring reports for NPR."He is being detained for questioning and a formal arrest warrant will be issued if there is sufficient evidence," Skyring says. "Police are also trying to establish whether others assisted Amri to plan and carry out the attack."Meanwhile, European authorities continue to investigate how Amri, who had been flagged as a threat and marked for deportation months ago, traveled from Germany to Milan after the attack.The Associated Press reports: