BERLIN (Reuters) - German prosecutors brought charges on Tuesday against employees of weapons manufacturer Heckler & Koch, whom they accuse of illegally trafficking arms to Mexican federal states to which Berlin has prohibited gun exports.

In 2016, Heckler & Koch, one of the world’s best-known gunmakers, said it would no longer sign contracts to supply countries outside of NATO’s influence because it had become too difficult to obtain government approval for such deals.

However, the Stuttgart prosecutor’s office charged six Heckler & Koch sales employees with violating both the Foreign Trade and the War Weapons Control Acts for delivering rifles and accessories to four Mexican states to which Berlin had prohibited arms exports due to the human rights situation there.

The prosecutor’s office said the employees, whom it did not name, made 15 illegal deliveries between 2006 and 2009 and were aware that arms deliveries were sent to these states.

Anti-arms activists consider the Heckler & Koch trial important because they suspect that G36 rifles were used in the 2014 abduction and massacre by a gang of a group of trainee teachers in the southwestern city of Iguala.

German journalist Juergen Graesslin initiated the lawsuit with information he had collected.

“In the fall of 2009, I received a phone call from a Heckler & Koch employee who said ‘My company was doing illegal arms trading with the management’s knowledge’,” Graesslin told Reuters TV.

Graesslin, the head of a campaign named “Outcry - Stop the Arms Trade”, and a member of the Peace Cooperative Network, checked the material he received and found it credible.

The German company on Friday said it would collaborate with the investigation.

“Heckler & Koch is aware of its social and legal responsibility. As a result of the incidents, the company has made drastic and extensive changes to prevent such events from occurring in the future,” the company said in a statement.