Bangladesh police stand guard following the verdict in the trial of those accused of the murder of blogger and secular activist Ahmed Rajib Haider at a court in Dhaka in this file image taken Dec. 31, 2015. Police are currently investigating another killing, this time of communist blogger Shahjahan Bacchu who was shot to death on June 11. (Photo by Munir Uz Zaman/AFP)

A communist blogger critical of religions has been gunned down by unknown assailants in central Bangladesh, raising fears of a resurgence of Islamic militancy in the Muslim-majority country.

Shahjahan Bacchu, 55, a former district secretary of the Communist Party of Bangladesh, was gunned down in Sirajdikhan in Munshiganj district on June 11.

"Four attackers riding two motorbikes shot him at close range and he died on the spot," said Asaduzzaman, a local police officer, who added that investigations are ongoing.

Bacchu's daughter Anchol Jahan said her father been on an Islamic militants' hitlist since 2013.

"My father was a freethinker blogger and his writings were critical of religions," said Jahan, who was Bacchu's daughter from his second marriage.

"He received death threats on the phone twice," she said.

"For the past three years, he has been living with us in our village, while my stepmother lives in Dhaka with my stepsisters. We suspect he has been murdered by extremists for his critical writings on religions," she added.

Bacchu was also the owner of a Dhaka-based publishing house.

Theophil Nokrek, secretary of the Catholic Bishops' Justice and Peace Commission, said he thought Islamic hardliners might have carried out the murder.

"He used to write poems denouncing religious extremism and was very vocal against religious fundamentalism. This condemnable killing shows radicalism has not been uprooted and it can bite back anytime," Nokrek told ucanews.com.

Mujahidul Islam Selim, president of the Communist Party of Bangladesh, condemned the killing in a statement.

"The murder of Shahjahan Bacchu exposes the poor state of law and order in the country. This is unacceptable and the government must take measures to arrest the killers and put them on trial," said Selim.

Long known as a moderate Muslim-majority country, Bangladesh has seen a sharp rise in Islamic militancy since 2013. Hardliners have murdered about 50 people including so-called atheist (secular) bloggers, writers, publishers, religious minorities and foreigners.

In response, the government launched an anti-militancy crackdown, which saw some 50 suspected militants killed in raids and hundreds of militants including top leaders, financiers and sympathizers arrested.