Photo courtesy Avaaz

I’d been in Sri Lanka just three weeks when I first heard of someone disappearing. It was May 2009 and I got an anonymous email telling me that Stephen Sunthararaj, a human rights worker from northern Sri Lanka, had been abducted at gunpoint and taken away in a white van in the heart of Colombo. He had previously been detained by the police – on suspicion of what, it is not clear – then released for lack of incriminating evidence just before his abduction. I tried to contact one or two ministers, I think, but didn’t get through and my work once more turned to the war then still raging in the north. I bitterly regretted not following up the case. Months later I met a Westerner who had known Stephen Sunthararaj. At the mention of him at dinner, he wept.

Fast forward to this year. Five weeks ago Ramasamy Prabagaran, a businessman and, like Stephen, a Tamil, was snatched in front of his wife and three-year-old daughter just as they were getting home. He too was spirited away in a white van; he too has not been seen since. When we visited his home, his wife, Shiromani, with holy ash from the Hindu temple on her forehead, was able to welcome us with a smile. But her voice was anguished as she told of how the men wrestled with him as he screamed and tried to hang onto the gate, of how cars and people passed and did nothing to help. How would the enchanting young daughter, Nikita, be affected now and if her father doesn’t come back?

I haven’t met the abducted man, who’s known as Praba. It seems he’s reasonably well-off. A muscular man whose exercise treadmill we saw in the front room. A man photographed on holiday in Switzerland and meeting top Indian cricketers. He belongs to a small ethnic group – Tamils of Indian origin, who had nothing to do with the separatist war. But he had nevertheless been held by the security forces for over two years, accused of Tiger involvement, bitterly denying it, and – according to a government medical officer’s report – showing signs of severe torture – “inflicted intentionally”, as it put it. “They are trying to make me a Tiger but I am not a Tiger,” he cried during a fleeting meeting with his wife during that time. But in September he was at last freed for lack of evidence. Two days before his complaint of torture came up in court, he was abducted. Where is he now?

There is a feeling of helplessness surrounding such events. This is the second time in nine months that I have covered the issue as a journalist.

Unfortunately “white vans” are the subject of a sort of grim humour in this small, intimate city. You talk with friends about someone doing something risky. Then you say: I hope a white van doesn’t come for him. The history of these sinister vehicles with false number plates goes back at least 20 years. But the war has now been over for three – yet the vans continue their cruel operations.

Human rights campaigners documented 32 unexplained abductions and disappearances between October and February. There was another this week, plus an apparent attempted abduction. The victims have been of all ethnic groups: Sinhala, Tamil, Muslim. Only five victims escaped, while seven bodies were found and the rest have vanished.

Arumugan Weeraraja is a labourer who struggled to educate his son, Lalith. He asked him not to get involved in politics. But Lalith, and a friend, Kugan, did. They organised demonstrations by families of disappeared people from the former war zone. In December they themselves were disappeared in Jaffna in the north, as if being taught a grim lesson for daring to speak up. No locals dared testify about what they witnessed. “I’ve asked at all the police stations, but none can help me,” said the father, tearfully, at a news conference.

A shocking thing has been the brazenness of several incidents. Both Stephen, a few years ago, and Praba were taken after being cleared in court cases. Another man was whisked away from the very arms of prison guards outside the Colombo Law Courts.

It isn’t just government critics who have vanished, or those it was seeking to implicate in terrorism. Some victims are those whom the authorities and the highly partial media denounce as being part of the criminal underworld. Even some figures until recently associated with the government are disappearing, especially since October when there was a fatal shooting incident involving two rival government strongmen.

When I met the genial police spokesman, Superintendent Ajith Rohana, he said time and again that the police were trying to solve these cases and the government wasn’t involved. I asked him whether we aren’t now talking about death squads in Sri Lanka. “Not at all. We totally deny that allegation,” he insisted.

But if unaccountable gangs roam around in vans, removing people who are usually never seen again – regardless of who sent these men, what are they other than death squads?

In its report in December, the internal war commission set up by President Rajapaksa said, quoting one witness: “Disappearance is far worse than death… When a person has disappeared, it is an eternal suffering.”

So I would ask the Sri Lankan leadership: Where is Ramasamy Prabagaran? Where are Lalith and Kugan? Where is Stephen? Where are Prageeth, Upali and others whose cases I reported earlier – and so many others beyond that?

I wonder if I will get answers – and whether their distraught families will.

[Editors note: This is article expands on the BBC Radio podcast first broadcast on 13 March 2012. Watch video of this story on the BBC here.]