On Monday, in the aftermath of bombings that ultimately left more than 300 people dead, Sri Lankan President Maithripala Sirisena announced a nationwide state of emergency, which will dramatically expand security forces’ ability to detain and question suspects in the attacks.

So far, some 40 people have been arrested in connection to the coordinated bombings, which targeted churches and hotels on Easter Sunday. The Associated Press reported that some of those who have been arrested so far include the driver of a vehicle that allegedly transported some of the suicide bombers, as well as the owner of a property where some of them allegedly lived. As The Washington Post reported, at least three are being held by the Terrorist Investigation Department, and lawmakers warned that others linked to the perpetrators may still be armed and on the run.

But as Sri Lanka seeks to establish order in the aftermath of the attacks, human rights experts are urging officials to carefully consider how they treat suspects. The emergency laws enacted Monday will be familiar to many Sri Lankans because the government relied on such powers to crack down on suspected rebels during its decades-long civil war. They were also briefly enacted last year after communal violence broke out in part of the country.

The country’s civil war ended in 2009, but human rights groups say a controversial anti-terrorism law enacted in the 1970s is still in effect, allowing security forces to detain suspects without warrants and keep them behind bars for up to 18 months without their having to appear in court. That law was used throughout the country’s conflict, and the emergency powers put in place this week offer security forces even more sweeping ability to detain suspects without court orders.

Sirisena has pledged to replace the country’s anti-terrorism legislation, but the government has so far failed to do so, raising concerns among human rights experts, who say they have documented cases in which detainees in Sri Lanka have been tortured and sexually abused in custody.

U.N. officials have also raised concerns over the treatment of Sri Lankan detainees. In 2016, Juan Mendez, then-U.N. special rapporteur on torture, said that in Sri Lanka, fewer cases of torture are reported now than were during the civil war, but that “the practice of interrogation under physical and mental coercion still exists and severe forms of torture …. continue to be used.”

Since arrests were made related to this week’s bombings, “we are not getting a lot of information about what is happening to those who are arrested,” said Thyagi Ruwanpathirana, South Asia regional researcher at Amnesty International. And it’s not clear whether they were arrested under the emergency provisions or under the counterterrorism legislation.

But in the aftermath of such attacks, “minorities tend to bear most of the brunt,” she said. In Sri Lanka, a majority-Buddhist country, “there was already a growing sentiment against Muslims,” Ruwanpathirana noted, raising further concern that the nature of the attacks and the Islamic State’s claim of responsibility could fuel existing religious tensions. And for detainees in Sri Lanka, “torture is rife,” she said.

Meenakshi Ganguly, South Asia director at Human Rights Watch, said Sri Lanka is still dealing with the aftermath of previous security operations and that the families of people who disappeared in earlier crackdowns are still searching for answers. “They have responded to terror threats in the past in a way that has not been rights-respecting,” Ganguly said of Sri Lankan security forces. “We are very concerned that none of that be repeated this time.”

In the final weeks of the country’s brutal civil war, “people were picked up and executed; there were allegations of rape,” she said. This time, Sri Lankan authorities should prosecute the perpetrators, she said, but “not repeat the mistakes of the past."

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