Kumi Naidoo is the secretary general of Amnesty International. The views expressed in this commentary are his own. View more opinion on CNN.

(CNN) The enforced disappearance and killing of Saudi journalist Jamal Khashoggi, last seen entering the Saudi Arabia consulate in Turkey on October 2, shows just how brazen the Saudi authorities have become in crushing dissent.

When Khashoggi, a prominent reporter and political commentator, entered the consulate in Istanbul to obtain personal documents earlier this month, he likely knew how dangerous it could be.

Picking up documents from your consulate should not carry a risk to your life. However, given that Khashoggi was forced into self-exile following a wave of arrests targeting journalists, academics and activists last year, he likely knew that it would carry some risk.

In the meantime, Saudi Arabia has now claimed that Khashoggi was accidentally killed at its consulate.

As gruesome details surfaced in the media over the past weeks about what reportedly happened to Khashoggi, President Donald Trump, arguably one of the Saudi government's staunchest allies, speculated that perhaps "rogue killers" were responsible . The official Saudi version seems to be an iteration of this idea -- not that the act was carried out by individuals acting on their own, but that Saudi officials suddenly went "rogue" and killed Khashoggi in a "fistfight."

But the Saudi line would have been laughable if the case were not so tragic.

The world needs to understand that for the Saudi government, killing Khashoggi was not "rogue," it was not the exception -- it was the rule. Amnesty International and others have documented endless laws, policies and individual cases in Saudi Arabia where the government and its officials have similarly flouted people's right to life, equality, justice and practically any other human right.

Khashoggi's remains must urgently be handed over so that an autopsy can be performed by independent forensic experts applying international standards for such investigations, following which the body should be handed over to his family so they can hold a proper burial. Until that happens, the truth remains elusive.

Meanwhile, the case has sent shock waves through Saudi Arabian human rights defenders and critics everywhere, diminishing any hope they have of seeking safe haven abroad.

If we are shocked by the alleged actions of the Saudi authorities, we shouldn't be.

These horrendous events fall squarely within a long-standing pattern of behavior of a government that ruthlessly hunts down its critics, with no fear of reprisals or pushback from the international community.

Saudi authorities have escalated their crackdown on dissenting voices in the country since Mohammad bin Salman became crown prince in June 2017. In the past year, Amnesty International has documented the systematic repression of anyone who has tried to stand up for the rights of ordinary Saudis and anyone with an independent voice. This pattern of repression started long before MBS, but has undoubtedly intensified and become more blatant under his leadership.

Among the most prominent cases have been those of women's rights defenders Loujain al-Hathloul, Iman al-Nafjan and Aziza al-Yousef. They have been arbitrarily detained without charge since May. The cruel irony is that these women were the leading campaigners against the driving ban for women that the Crown Prince has now overturned. Al-Hathloul, al-Nafjan and al-Yousef may face trial before a counterterror court and risk a lengthy prison sentence.

We also cannot rule out the possibility that Saudi authorities would seek the death sentence against activists and others currently detained without charge who were simply protesting peacefully. As one of the world's most prolific executioners , we know Saudi Arabia can carry out death sentences against citizens who express dissent following seriously flawed trials.

It should be obvious by now that for the people who suffer most at the hands of the Saudi government, the stakes could not be higher. Yet Saudi Arabia's crackdown on human rights has by and large been met with deafening silence by the international community. Governments have instead chosen to continue peddling trade deals -- including arms -- with Saudi Arabia, while avoiding any criticism of its human rights record.

When Canada spoke out this August against the arrest of women's rights activists, Saudi Arabia launched an aggressive and punitive diplomatic counterattack. And again, other nations chose to say silent. This collective silence and lack of consequences empower the Saudi Arabian authorities to dismiss human rights concerns and continue to crush dissent. The consequences for human rights defenders and civil society in Saudi have been truly disastrous.

It should not take a horrendous, high-profile incident like this for the world to wake up to the plight of human rights defenders and others in Saudi Arabia, not to mention its involvement in the war in Yemen, which has led to a humanitarian catastrophe on an unimaginable scale.

The international community now must ensure that Khashoggi's enforced disappearance and killing is the final straw. If this brazen act goes unanswered, it sends a truly horrible message to repressive leaders everywhere about what they can get away with, if only they have enough political cover.

The most urgent step is for the UN Secretary-General Antonio Guterres to establish a UN investigation into the circumstances surrounding Khashoggi's extrajudicial execution, possible torture and any other crimes and violations committed in his case.

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We cannot allow Saudi Arabia to act with impunity, not least because of the dangerous -- indeed lethal -- implications for activists and members of civil society, especially those who are in detention right now.