The killing of three people by suspected Islamist extremists in Bangladesh in two days has heightened concerns about the safety of advocates of secularism and free speech in the mostly Muslim nation.
Here is a list of attacks on secular writers, publishers and members of Bangladesh's minority Shiite and Christian communities, starting in 2013:
— Feb. 15, 2013: Assailants wielding machetes kill secular blogger Ahmed Rajib Haider after he posts comments online about religious fundamentalism. In December 2015, police arrest eight people they suspect of having links with the banned group Ansarullah Bangla Team
— Feb 27, 2015: At least two assailants attack Bangladeshi-American blogger and writer Avijit Roy with meat cleavers, killing him and injuring his wife on a crowded street in Dhaka, the capital. A previously unknown group, Ansar Bangla 7, which intelligence officials believe is part of Ansarullah Bangla Team, claims responsibility. At least four suspects are arrested.
— March 30, 2015: Three men use meat cleavers to hack 26-year-old blogger Washiqur Rahman Babu to death in Dhaka. Bystanders chase down two of the attackers, but a third escapes. The captured suspects say they are students at Islamic schools and were ordered to commit the crime. Police have been unable to determine who gave the order.
— May 12, 2015: Four men with meat cleavers kill online atheist activist and science magazine editor Ananta Bijoy Das as he leaves his home in the northeastern city of Sylhet. Police arrest a newspaper photographer and two others. Al-Qaida on the Indian subcontinent, which is believed to be affiliated with Ansarullah Bangla Team, claims responsibility.
— Aug. 8, 2015: A fourth blogger, Niloy Chottopadhay, is killed by men who enter his Dhaka apartment, posing as potential tenants, and assault him with cleavers. Ansarullah Bangla Team claims responsibility in an email, though the authenticity of the message has not been confirmed.
— Sept. 28, 2015: Three assailants on a motorcycle gun down Italian citizen Cesare Tavella in Dhaka's diplomatic quarter. The Sunni extremist group Islamic State claims responsibility, according to the terror monitoring group SITE. Officials reject the claim and accuse local Islamist groups of attempting to destabilize the country. A month later, police arrest four suspects who say they were hired by "a big brother" to attack "a white man" to create chaos in the country, according to authorities.
— Oct. 4, 2015: Masked assailants on a motorcycle kill Japanese citizen Kunio Hoshi, who was working in agriculture in northern Bangladesh. The Islamic State group claims responsibility, but the government again dismisses the idea that the group has any presence in the country.
— Oct. 24, 2015: Attackers hurl homemade bombs into a crowd of thousands of Shiite Muslims as they gather for a pre-dawn religious procession in Dhaka. A teenage boy is killed and more than 100 other people are injured. Police arrest two suspects and recover two unexploded bombs. They dismiss an IS claim of responsibility and say the culprits were likely from the banned local group Jumatul Mujahedeen Bangladesh. On Nov. 26, security forces arrest six suspects after a gunfight that killed the group's alleged military commander.
— Oct. 31, 2015: A group of men hack to death a publisher of secular books and wound three others in Dhaka. The publisher, Faisal Arefin Deepan, had close ties with killed blogger Roy. The banned group Ansar al-Islam claims responsibility.
— Nov. 26, 2015: At least five gunmen open fire on Shiite Muslim devotees during evening prayers at a mosque in northern Bangladesh. An elderly mosque official who had been leading the prayers is killed and three others are wounded. A group describing itself as an IS affiliate in Bangladesh claims responsibility and vows more attacks. Police detain two suspects for questioning
— Feb. 21, 2016: Two men armed with guns and cleavers hack a Hindu priest and removing his head at a temple in northern Bangladesh, an attack later claimed by the Islamic State. The men escaped the crime scene on a single motorcycle, but within days police arrest three suspects. The government also dismisses the IS claim.
— April 6, 2016: Student activist for secularism Nazimuddin Samad is hacked and shot to death as he was walking home with a friend after attending an evening law class at a Dhaka university. The three masked assailants escape on a motorcycle while shouting "Allahu Akbar," or "Allah is great." The banned group Ansar-al-Islam, the Bangladesh division of al-Qaida in the Indian Subcontinent, or AQIS, claims responsibility in the name of "vengeance."
— April 23, 2016: Professor A.F.M. Rezaul Karim Siddique is hacked to death on his way to work at the state-run university in the Bangladeshi city of Rajshahi, where he taught English. The Islamic State group claims responsibility, but the government dismisses the claim and instead blames local religious radicals.
— April 25, 2016: Unknown assailants fatally stab USAID employee Xulhaz Mannan, who previously worked as a U.S. Embassy protocol officer and was an editor of Bangladesh's first gay rights magazine, as well as his friend, Tanay Majumder. There is no immediate claim of responsibility.