August 30 marks the International Day of the Victims of Enforced Disappearances. For Salam Al Hashimi, an Iraqi refugee in Finland, this day is another stark reminder that his son Wissam, who was abducted by US soldiers in Baghdad in 2005, has been missing for almost 13 years.

Wissam, 21 at the time, was a contractor with the US forces and worked on the maintenance of Baghdad Airport Road. On October 16, 2005 – the day of the constitutional referendum – he was arrested by three US soldiers in front of the Babylon Hotel, 300 metres from his house, where he was going to meet his supervisor.

His arrest took place in plain sight and was witnessed by a friend of his father’s. His family has not heard from him since, despite their repeated attempts to find him.

“After his arrest and up to 2007, I would go to the Green Zone every month to ask the US forces to search for my son’s name in their database. They repeatedly told me that they could not find his name. I also went to all US military bases and detention facilities in the region, their answer was the same every single time: his name is not in the database,” he recalls.

From 2008, Salam tried to reach out to the Iraqi authorities: he wrote to the former Prime Minister Nouri al-Maliki and even met with one of his staff, who promised him answers. However, he never heard from him again. In 2011, he contacted the defence and justice ministries, to no avail. The human rights ministry wrote back to him, but only to say that they had no information.

Salam had a glimpse of hope when, almost six years after his son’s arrest, former detainees told him that they had seen him in Camp Cropper, a US detention centre located near Baghdad’s airport, in July 2011. This was right before US military officials handed over the facility – and its 1,600 prisoners – to the Iraqi authorities.

“For me, this was confirmation that my son had been secretly detained by the US forces all these years and that they did not want to acknowledge his detention,” he says.

Hoping that international pressure would help clarify his son’s fate, Salam brought Wissam’s case to the attention of the United Nations Working Group on Enforced or Involuntary Disappearances (WGEID), which acts as a channel of communication between families of disappeared persons and governments.

The UN experts sent a letter to the US government in 2016 asking for clarification, but the authorities’ reply was no different from what Salam had been told before: They had “searched their records” and were “unable to find a match”.

This answer can only mean one of two things: it is either a refusal on the part of US authorities to recognise their responsibility in Wissam’s enforced disappearance and/or an acknowledgment that they were not keeping proper records of individuals under their custody, in violation of their international obligations.

The 2008 Status of Forces Agreement established that US troops would leave Iraq by the end of 2011, and either release or transfer custody of all detainees to the Iraqi authorities. As of 2009, US forces were officially holding over 15,000 individuals, the vast majority of whom had never been charged or tried. However, the list of detainees transferred from US to Iraqi custody was never made public and to this day, thousands of families – like Wissam’s – are left in the dark.

While some abuses committed by US forces received considerable media coverage – most notably the practice of torture in Abu Ghraib – the plight of families of disappeared at the hands of US soldiers has remained under the radar, and an issue few people are aware of.

Iraq has the highest number of disappearances of any country worldwide, with estimates ranging from 250,000 to one million missing persons. The practice emerged during the Baathist era, continued during and after the US occupation and recently peaked in the context of the fight against the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group.

The crime of enforced disappearance is qualified as one of the most serious human rights violations under international law due to the double suffering it causes: For the victims themselves, who are placed outside the protection of the law, and for their families who are subjected to the constant psychological torture of not knowing the fate and whereabouts of their loved ones. When used in a widespread or systematic manner, the practice of enforced disappearance amounts to a crime against humanity.

Neither the US nor the Iraqi authorities have ever recognised their responsibility in enforced disappearances committed after the 2003 invasion. The Iraqi government argues that Iraq “suffered from enforced disappearances because of the dictatorship in the past”, denying that the practice continues to this day. The fact that Iraqi legislation only criminalises enforced disappearance as a crime against humanity in relation to offences committed between 1968 and 2003 is illustrative of this denial.

It is to shed light on this crime and provide assistance to other families of the disappeared that in 2007, Salam founded the NGO Al Wissam Humanitarian Assembly, named after his son. For the past four years, we have been taking various actions together, including the submission of more than 100 cases to the United Nations Committee on Enforced Disappearances (CED). However, his activism has been risky: he and his colleagues have been repeatedly subjected to reprisals and threats.

In late 2015, Salam was informed that an arrest warrant had been issued against him and that he was wanted for “terrorism”, a trumped-up accusation aimed at deterring him from carrying out his work and often used in Iraq to silence peaceful criticism. Despite the intervention of the UN secretary-general who denounced these acts of retaliation in 2016, Salam continued to fear for his life and was forced to flee to Finland where he obtained refugee status.

“My only desire is to be able to go back to Iraq and continue looking for my son. I would not wish the pain of having to live with the disappearance of a loved one, even on my worst enemy. Nobody can begin to imagine the extent of our suffering and how this turned our lives upside down. In the face of such a tragedy, some cannot stand it and give up, and some have increased resilience that keeps them searching for the truth,” he says.

Salam falls firmly within the latter category. He remains one of the most dedicated human rights defenders that I have ever encountered.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial stance.