It’s been a tough few months for German arms manufacturer Heckler & Koch (H&K).

Its guns are being abandoned by the German armed forces, and a swathe of accusations have piled up: ‘cronyism’ with the German ministry of defence; trying to use German military intelligence to quash negative media coverage; and most importantly, illegally selling thousands of guns to Mexico, according to Germany’s Customs Investigation Bureau (ZKA).

The ZKA report suggests that a lawsuit will be brought against 5 former executives and employees of the company, and that H&K could be fined $3.3 million (the value of the sales).

In 2007, the German government banned the export of arms to the Mexican states of Chihuahua, Jalisco, Chiapas and Guerrero, due to concerns that they could be used in cases of human rights violations.

However, according to reports published in the German newspaper Süddeutsche Zeitung, H&K delivered over 9,000 G36 assault rifles to Mexico between 2003 and 2011 alone, with over half of them going to the regions covered by the ban.

Sales like these don’t just have legal consequences; they also have grave human ones. The authorities in Guerrero are routinely linked to corruption and human rights abuses. In 2011, photographs and witness testimonies emerged, which indicated the police had turned H&K rifles on a student protest, killing 2 innocent people in the process.

The abuses have got even worse since then. 2014 saw the kidnapping and murder of 43 students in an event that prosecutors believe was carried out by gangsters with the full knowledge and complicity of the police.

Officers have been accused of rounding up the students and handing them over to the Guerreros Unidos drug gang, which slaughtered them and incinerated their bodies.

The massacre led to a major investigation, with state and federal officials being called in from across the country. Upon searching through the police arsenal, the investigators found a cache of H&K G36 rifles. It is still unclear if the Iguala police used the G36s during the initial attack on the students. It is however known that they used 5.56-millimetre rounds, which would fit the G36.

An investigation into the wider issue of arms sales to Mexico has been going on for 5 years. However, despite conducting several interviews and raiding the company’s headquarters and the homes of executives, the German authorities are yet to formally report back or to charge anyone.

There is little doubt that the guns were sold.

In 2013, an H&K internal investigation into the same issue found 2 employees had sold weapons to the banned regions. Both employees were quickly removed from the company.

However, last January, the employees won an unfair dismissal case in a labour court after their sacking was deemed unlawful.

A final verdict on the arms sales is expected soon, but, regardless of what comes out, it is clear that the problem goes deeper than a few rogue employees.

Heckler & Koch has a long and shameful history of evading arms embargoes to supply conflict zones and repressive regimes. One trick the company has used many times is to license a country that isn’t bound by embargoes to manufacture and sell H&K’s weapons.

For example, in the 1970s, German companies weren’t allowed to sell arms to Kenya, but H&K got around this by licensing the UK’s Royal Ordnance Factories to make and sell 200,000 battle rifles to Kenya.

The company has been using this trick ever since, and in 2008 it licensed Saudi Arabia – one of the world’s most repressive regimes – to manufacture G36 rifles, which they then proceeded to sell on the international market.

H&K guns have been used in ethnic cleansing in Kosovo and Darfur, and its G36 rifles have turned up in Georgia and in Qadafi’s arsenals in Libya, despite exports to these conflict zones being illegal under German law.

The issue, however, goes further than Heckler & Koch.

Corruption and the arming of human rights abusers are endemic in the global arms trade. Europe’s biggest arms company, BAE Systems, has been widely accused of bribery and corruption, and has sold weapons to human rights-abusing regimes all over the world, including Bahrain, Egypt, Saudi Arabia and Libya.

Similarly, teargas canisters produced by British arms company Chemring have been used against innocent people in Egypt and Hong Kong.

The other crucial part of the equation is the role of governments.

Companies like H&K sell weapons all over the world, but they wouldn’t be able to do so without the support and complicity of governments that promote their products and license their exports.

Despite recent talk from the German government about reducing it, the German arms trade is currently the third biggest in the world.

What is required is not the removal of a handful of executives, it is a radical change in policy and an end to a trade that exacerbates violence and profits from conflict. There can never be an ethical arms trade, because it is a contradiction in terms.

The products made by companies like Heckler & Koch do not make the world more secure; on the contrary, they fuel conflict and facilitate human rights abuses such as those seen in Mexico.

Germany, Britain, and the other countries that promote and aid companies such as H&K could stop the sale of arms to conflict zones and tyrants right now; all it would take is political will.

Andrew Smith and Kirk Jackson are spokespeople for Campaign Against Arms Trade (CAAT). You can follow CAAT at @CAATuk.