AS IF the collapse of the Rana Plaza factory building, where the death toll has now topped 900, was not enough, now come fresh deaths in Bangladesh from political violence. What happened in Dhaka and beyond in the early hours of May 6th looks like a massacre.

European diplomats say as many as 50 people were killed in the capital as security forces cracked down on members of an extreme Islamist group, Hefajat-e-Islam. Many more were killed elsewhere. Odhikar, a reputable human-rights outfit, reports that some hundreds of people died during a “killing spree” by a force of 10,000 made up of police, paramilitaries and armed men from the ruling Awami League. Bodies were strewn about the streets of Dhaka’s commercial district. Deadly clashes took place elsewhere, such as at Narayanganj, south of the capital, where 20 people were reported killed.

Just what happened remains murky, not least because a cowed local press has kept largely silent. Before opening fire in Dhaka, police cut the power supply in the city’s commercial area. The idea seems to have been to flush out tens of thousands of often violent demonstrators, mostly young students who had flocked in from madrassas in rural Bangladesh.

They belonged to Hefajat, a banner for a set of Islamist splinter groups little known until now. Drawing support mostly from madrassas near Chittagong, a southern port city, it recently declared national aspirations. In April hundreds of thousands of Hefajat supporters marched on Dhaka, issuing 13 demands that they said the government should meet by the end of the month. These included the introduction of an anti-blasphemy law carrying the death penalty for anyone who “insults” Islam. Other Taliban-style demands were for an end to Bangladesh’s pro-women development policy; a ban on men and women mixing in public; an end to “shameless behaviour and dresses”; and a call for the gentle Ahmadiyya sect to be declared non-Muslim.

Such regressive calls go entirely against the moderate Islam practised by most Bangladeshis, and against the country’s generally secular political tradition. Yet, disturbingly, the main opposition, the Bangladesh Nationalist Party (BNP), backed Hefajat. The BNP’s Islamist credentials are growing more explicit. It remains allied to Jamaat-e-Islami, a religious party that serves as a standard-bearer for Saudi Arabia’s strident strand of Islam. In April Khaleda Zia, the BNP’s leader, hosted a meeting of Arab envoys in what appeared to be a show of support by the diplomats for the party.

The politics of religion matters in Bangladesh. Even the supposedly secular Awami League talks up its Islamic credentials before elections. In 2006, for example, the League struck an electoral deal with the ultra-orthodox Khelafat-e-Majlish party, promising to do much of what Hefajat wants today. It was never tested, since the subsequent elections were scrapped.

This time around, ahead of elections that must take place by January 2014, the League is also careful to be seen as pro-Islam. Last month police were sent to arrest four atheist bloggers. On May 6th Hefajat’s 90-year-old leader was flown to Chittagong in a demonstration by the authorities that he had not been arrested.

The coming months look turbulent. A war-crimes tribunal will continue issuing verdicts on trials of Islamist hardliners, nearly all of them leaders of Jamaat, over atrocities committed during the 1971 war of independence from Pakistan. One guilty verdict in February led to violent protests and the deaths of at least 67. On May 9th the tribunal sentenced Jamaat’s deputy head, Muhammad Kamaruzzaman, to death for crimes against humanity. Bangladesh will brace for more bloodshed.