In 2009 Sri Lanka mercilessly crushed its decades-old Tamil insurgency, in effect ending the Sri Lankan civil war. Now, nearly three years later, one of the ugliest trends of the war is re-emerging: disappearances. Two human rights activists went missing in December on their way to an anti-government rally. They're not the only ones.

Sri Lanka's endangered Tigers

From the early 1980s until 2009 the Liberation Tigers of Tamil Eelam (LTTE), known as the Tamil Tigers, waged a fierce separatist war against the central government of Sri Lanka. Under secretive leader Vellupillai Prabhakaran, the Tamil Tigers – self-appointed liberators of Sri Lanka's Tamil minority – became renowned for their fighting prowess. The rebel group waged a ruthless revolt of ambushes, head-of-state assassinations and suicide attacks.

The government's campaign against the Tigers was no less ferocious. After peace talks in the early 2000s fell flat, Sri Lankan forces launched an all-out offensive against the Tigers. The onslaught, marked by indiscriminate shelling of trapped civilian populations, successfully broke the Tamil Insurgency and left Prabhakaran and many of his chief lieutenants dead. According to UN figures, 40,000 Tamil civilians were killed in the final government push of 2008-2009.

The new missing

During the civil war, the Sri Lankan government detained thousands of civilians in the rebellious north. Years later, the fate of many of the disappeared remains a mystery: at least 6,000 Sri Lankans are still being held under various security laws. Two human rights activists, Lalith Kumar Weeraraj and Kugan Muruganathan, have worked to bring attention the cause, calling specifically for answers on the whereabouts of hundreds of Tamils last seen in government custody.

Last year, they organized a series of protests in capital city Colombo for the families of the missing. In December, Weeraraj and Muruganathan planned another rally in the northern city of Jaffna – a flashpoint of the civil war where the army maintains a large presence. On their way to that rally they were intercepted by men on motorbikes and ferried away in a white van. Nothing has been heard from them since.

Others have gone missing too. And not just Tamils. There have been reports of at least nine abductions in the past few months – most in or around Colombo. A local paper's account of the abductions noted the repeated presence of unmarked white vans. Two of the abducted men, a Muslim astrologer named Mohamed Niyas and 25-year-old Buddhika Charitananda, were later found dead.

Who's to blame?

Last year, Sri Lanka axed its long-reviled emergency law, but it retained a collection of national security statutes that enable detention without charge for up to 18 months. New legislation has also been proposed that would authorise the government to continue to hold thousands of detainees under various security pretexts.

There is no definitive evidence linking the government to the recent spate of abductions, but a government-appointed body did issue a report in December noting an alarming number of alleged “abductions, enforced or involuntary disappearances, and arbitrary detentions”.

Before his abduction Weeraraj – of mixed Sinhalese and Tamil descent – had twice been detained by men alleged to be Sri Lankan military. He also told a BBC reporter that he was being shadowed by security officials. Muruganathan's motorbike was allegedly found inside a Jaffna police station. There's been lots of speculation over who's responsible for the kidnappings – drug gangs? Hitmen? But regional human rights groups have little doubt who's to blame.

Further Reading:More information on the disappearances of Sri Lankan activists and ways to help secure their release.