In a letter to a friend in Europe, Abdul Razaq al-Na'as, a Baghdad university professor in his 50s, grieved for his killed friends and colleagues. His letter concluded: "I wonder who is next!" He was. On January 28 al-Na'as drove from his office at Baghdad University. Two cars blocked his, and gunmen opened fire, killing him instantly.

Al-Na'as is not the first academic to be killed in the mayhem of the "new Iraq". Hundreds of academics and scientists have met this fate since the March 2003 invasion. Baghdad universities alone have mourned the killing of over 80 members of staff. The minister of education stated recently that during 2005, 296 members of education staff were killed and 133 wounded.

Not one of these crimes has been investigated by the occupation forces or the interim governments. They leave that to international humanitarian groups and anti-war organisations. Among them is the Brussels Tribunal on Iraq, which has compiled a list to persuade the UN special rapporteur on summary executions to investigate the issue; they do so with the help of Iraqi academics, who risk their lives in the process. Their research shows that the victims have been men and women from all over Iraq, from different ethnic, religious and political backgrounds. Most were vocally opposed to the occupation. For the most part, they were killed in a fashion that suggests cold-blooded assassination. No one has claimed responsibility.

Like many Iraqis, I believe these killings are politically motivated and connected to the occupying forces' failure to gain any significant social support in the country. For the occupation's aims to be fulfilled, independent minds have to be eradicated. We feel that we are witnessing a deliberate attempt to destroy intellectual life in Iraq.

Dr al-Na'as was a familiar face on al-Jazeera and al-Arabiya TV. He had often condemned the continued presence of US-led troops in Iraq, and criticised the sectarian interim governments and their militias. His case echoes the assassination of the academic Dr Abdullateef al-Mayah. A prominent human rights campaigner and critic of the occupation, Mayah was killed only 12 hours after he had appeared on al-Jazeera denouncing the corruption of the US-appointed Iraqi Governing Council.

Militias have replaced the disbanded Iraqi army, applying their own rule of law. Some units operate under a semblance of "legality" - the "wolf brigade", attached to the interior ministry, is infamous for its terror raids on mosques and the torture of civilians.

Last month the journalist Abdul Hadi al-Zaidi accused the government's militias of targeting intellectuals. He is one of a group of Iraqi journalists who, in the aftermath of al-Na'as's assassination, went on strike, demanding an immediate investigation into the "systematic assassination campaign" against intellectuals opposed to the occupation.

After the July London bombings, Tony Blair promised the British people to "bring those responsible to justice". In Iraq, the British government does exactly the opposite. The law of occupation states that: "All foreign soldiers, diplomats or contractors implicated in the killing of Iraqi civilians are immune from arrest or trial in Iraq." Both the British and US governments turn a blind eye to the systematic violations of human rights and murders committed by their clients in Iraq.

It has become obvious that the occupation forces, with their elite troops and $6bn-a-month budget, cannot hold Iraq. The only honorable and realistic way out is genuine dialogue with the Iraqi resistance over a complete withdrawal of foreign troops and adequate reparations and debt-cancellation to rebuild the country.

· Haifa Zangana is an Iraqi-born novelist and former prisoner of Saddam's regime; a longer version of this article will appear in Not One More Death, published next month by Verso

haifa_zangana@yahoo.co.uk