Bangladeshi teachers, students and social activists hold banners and sing songs during a protest against the killing of a University Professor A.F.M. Rezaul Karim Siddique in Dhaka, Bangladesh, Friday, April 29, 2016. (AP Photo)

A Sufi Muslim spiritual leader was found hacked to death in a mango orchard in the Rajshahi district of northwest Bangladesh on Friday, the latest victim in the recent string of brutal attacks across the country targeting religious minorities, academics, secular bloggers and activists.

Abdur Razzak, an officer from the local Tanor Police Station told news outlets that the body of Mohammad Shahidullah, 65, was recovered at around 10 pm on Friday night.

"It seems he was hacked first," Razzak said. "And then slaughtered." He was reportedly murdered after leaving a meeting organized by other Sufis.

The police superintendent said that the manner of Shahidullah's murder appeared to be in keeping with others carried out recently, but that authorities weren't certain there was a link.

Sufism is a school of Islam known for its mysticism. Though it is popular in Bangladesh, the majority of Bangladesh's population is Sunni.

Last week, a Hindu tailor was hacked to death as he was sitting outside his shop in the central city of Tangail. His death was claimed by Islamic State (IS). According to the US-based monitoring group SITE, militants killed Nikhil Chandra Joarder, 50, for allegedly blaspheming the Prophet Mohammed. Hindus are a religious minority in Bangladesh, and make up about nine percent of the population.

Days before Joarder's murder, a prominent gay rights activist and editor of the country's only LGBT magazine, and his friend were hacked to death in a Dhaka apartment. An English professor was also hacked to death while on his way to work, supposedly on account of his "atheism." IS claimed responsibility for both of those deaths.

In February, a top Hindu priest was beheaded by militants inside a temple in northern Bangladesh. IS claimed responsibility for his death, but police found no connections between the three people they arrested for his murder and the terror group.

Authorities have consistently denied that IS are even active on Bangladesh soil.

On Wednesday, eight Bangladeshi men were detained in Singapore for planning attacks in their homeland. The men had allegedly formed an extremist cell, and were sharing radical propaganda and videos. They called themselves the Islamic State in Bangladesh (ISB), according to Singapore's Ministry of Home Affairs. Singapore officials said the group had a hierarchical structure with a leader, deputy leader, and people overseeing finances. The ISB had reportedly identified several possible targets in Bangladesh.

Last year, the Sunni terror group claimed responsibility for a number of attacks targeting Shiite Muslims and foreigners. Bangladesh officials doubted IS claims of responsibility and alleged that the group's leaders were simply seeking media attention.

Regardless of whether IS was responsible for recent deaths or not, organized extremist and militant groups have long existed in Bangladesh, which are becoming increasingly active and their victims increasingly diverse.

Bloggers and scientists, Hindus and humanitarians, free-thinkers and foreigners, religious minorities and academics, have all been targeted, many of them meeting similarly brutal ends as the Sufi spiritual leader.

Critics of Sheikh Hasina's government say she has failed to rein in extremist violence by failing to defend secularism and carrying out toothless investigations.

Last week, US Secretary John Kerry called on Hasina to offer support for the investigation into the attack that killed gay rights activist Mannan, urging her to double down on law enforcement efforts to prevent future attacks, and ensure recent murders are thoroughly investigated.

Hasina has previously pointed a finger at the country's opposition group, the Bangladesh Nationalist Party (BNP), and its allegedly "allied armed groups."

"The BNP-Jamaat nexus has been engaged in such secret and heinous murders in various forms to destabilize the country," Hasina said, referring to the outlawed, fundamentalist group, Jamaat-e-Islami. "Such killings are being staged in a planned way." The BNP described Hasina's accusations as "ridiculous and unfortunate."