The Islamic State group (IS) said it was behind the killing of a homeopath in western Bangladesh on Friday.
Mir Sanwar Rahman was hacked to death by three attackers with machetes riding a motorbike in Kushia district.
His friend, university tutor Mohammad Saifuzzaman, was seriously injured in the same attack.
There has been a series of murders of religious minorities, secular activists and academics in Bangladesh in recent months.
Both of the men attacked on Friday were said to be followers of the mystic tradition of Baul music, seen as heretical by some Muslims.
However, police said they were also investigating a possible personal motive for the killings.
IS made its claim on its Amaq news agency, saying Mr Rahman was killed for “promoting Christianity”.
Mr Rahman was known for giving out free homeopathic medicine. He and Mr Saifuzzaman were ambushed as they rode on a motorbike in their village.
Police official Proloy Kishim told the BBC Bengali service the two men had both been stabbed on the head and neck.
More than 20 people have been killed in attacks by suspected Islamists in the past three years.
An elderly Buddhist monk was hacked to death on Saturday, while a Hindu priest, two prominent gay activists, a law student and a university professor were also murdered in recent months.
The killings have been blamed on various hardline groups, including IS and Ansar al-Islam, a Bangladeshi militant group affiliated to al-Qaeda.
The government has denied that IS is present in the country. Instead, it has blamed opposition parties and local Islamist groups, such as Ansarullah Bangla Team and Harkatul Jihad.
The opposition have denied any involvement and say the government’s accusations against them have hampered a credible investigation.