Breivik was stopped during a routine check outside the Germany city of Wetzlar, located north of Frankfurt, probably in the beginning of 2009, ABC Nyheter reported.
“Three and a half years ago, I received information that the German authorities almost caught Breivik in 2009,” German documentary filmmaker Daniel Harrich said.
Harrich has for years researched the illegal arms trade in Europe.
Harrich's latest film's ‘Waffen für den Terror' (Weapons for Terror), which was recently aired on the TV channel Arte – includes the startling new revelation about the convicted Norwegian mass murder.
The information has created a stir amongst Norwegian police, which received no information about Breivik's Germany stop.
“Such a disclosure would be something that you would have noticed in an investigation of this sort,” police attorney Pål-Frederik Hjort Kraby told ABC Nyheter.
Harrich says he has at least three sources who independently confirmed the information.
According to Harrich's sources, the ammunition and some weapons parts were confiscated from Breivik while he was allowed to keep some parts that could not be directly tied to a functioning weapon.
The stop in Germany would have occurred more than two years before he killed a total of 77 people via a bomb in Oslo and a cold-blooded shooting spree at a youth summer camp on the island of Utøya.
Earlier this month, the Oslo district court ruled that Breivik's court case against the Norwegian state over his prison conditions, which he likens to "torture", will take place in March in the jail where he is being held.