Germany searches for possible accomplices of the suspected Berlin truck attacker Anis Amri, who was gunned down by Italian police, as Tunisia announced the arrest of three men linked to him. One of those detained is Amri's nephew. <br/><br/>Amri is believed to have hijacked a truck and used it to mow down holiday revellers at a Berlin Christmas market, killing 12 people. German security services have also faced criticism for not keeping better tabs on Amri before the Berlin carnage, even though he was a known criminal. <br/>