DHAKA:Police in Bangladesh have arrested the main suspect in the killing of a publisher who was hacked to death by Islamist militants last October, the head of the police counter-terrorism unit in Dhaka said on Wednesday.

A reward of 200,000 taka ($2,564) had been offered for information leading to the capture of Moinul Hasan Shameem, who police say had led the attack on the publisher by members of a banned Islamist group, Ansar al Islam.

The victim, Faysal Arefin Dipon, was regarded as secular in outlook and had published books written by his friend Avijit Roy, a U.S. citizen of Bangladeshi origin. Roy was killed in February last year. He was also hacked to death by Islamist militants.

On the same day that the publisher was killed, militants also attacked another publishing house, seriously wounding three people.

Police said Shameem, 24, took orders from a former army major, Syed Mohammad Ziaul Haque, who has emerged as a leading figure in Ansar al Islam.

"Shameem was the leader of that attacking group," Monirul Islam, Dhaka police counter terrorism chief, told reporters.

"After a tip-off, police arrested him from Tongi, on outskirts of the city on Tuesday night," he said.

Militants have targeted secularist writers in Bangladesh in recent years, as the government has cracked down on Islamist groups seeking to turn the South Asian nation of 160 million people into a sharia-based state.

On July 1, militants killed 20 hostages, most of them foreigners, in an assault on a cafe in an upmarket area of the capital.