Berlin truck attack suspect was under surveillance for months, say authorities

Latest: German authorities say the suspect in Monday's deadly truck attack in Berlin was under covert surveillance for several months this year.

Update 6.50pm: German authorities say the suspect in Monday's deadly truck attack in Berlin was under covert surveillance for several months this year.

Berlin prosecutors told The Associated Press that they launched an investigation against Anis Amri on March 14 following a tip from federal security agencies.