During a raid in Aldenhoven in the Düren district, investigators discovered an arsenal with war weapons.
The investigations were directed against a 32-year-old - initially only for violating the Foreign Trade Act, said a spokeswoman for the Frankfurt public prosecutor's office on Wednesday.
In a newly built district, however, the investigators came across firearms, grenades, hand grenades and mines.
That is why the accusation of violating the War Weapons Control Act was added.
The man should be brought before a judge in Düren on Wednesday.
According to the "Spiegel", the suspect is a captain and explosives expert in the Bundeswehr.
The public prosecutor did not want to confirm or deny this.
Radiation protection experts deployed
Because unknown chemicals were discovered in the house, the emergency services consulted an expert from the Federal Office for Radiation Protection to evaluate the findings.
The mission, which began on Tuesday, continued through the night into Wednesday and was not yet over in the early afternoon either.
Customs intercepted a package with silencers that the 32-year-old is said to have given up.
The authorities therefore initiated proceedings and obtained a search warrant.
A political background is currently not discernible, according to the public prosecutor's office.
According to the customs investigation office in Essen, some “substances” had to be destroyed on site.
These are said to be some of the chemicals.
According to the mirror, explosives were detonated from the discovered ammunition in the man's garden and thus rendered harmless.