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 Chiapas, Chihuahua, Guerrero and Jalisco are not permitted due to suspected police corruption.

Still, according to the investigation which was turned into a book, a documentary, and a fictional TV show for public broadcaster ARD, H&K delivered thousands of G36 assault rifles to the corrupted Mexican States between 2003 and 2011.

Deutsche Welle (DW) reported that according to a previously unpublished report from the Customs Criminal Office (ZKA) in Cologne, the arms company delivered some 4,767 G36 guns to the prohibited states. According to Deutsche Welle, the police department in the state of Guerrero which was involved in the missing students case in Mexico had G36 rifles.