A prosecutor asked for the opening of an investigation into four journalists and an activist, who revealed that German arms company, Heckler and Koch (H&K), illegally exported assault rifles to corrupt Mexican police forces.

The investigative journalists uncovered documents which suggest that the German government may have colluded with H&K to circumvent the German arms export laws. Under the German law, arms trade in Mexico is mostly permitted, but arms exports to the states of Chiap...