The murder was one of the first killings in a series of clandestine attacks on foreigners, Hindus and secular or moderate Muslim Sufis.
"They will be hanged until death," Judge Noresh Chandra Sarker of the Special Court in Rangpur pronounced as four of the five detained convicts were escorted to the courtroom under heavy security cover.
The judge acquitted two of the six accused in the murder of Kunio Hoshi, a Japanese farmer who set up a farmhouse in northwestern Rangpur town, while a fugitive convict was tried in absentia.
The Islamic State militant group had claimed responsibility for the attacks, but the government rebuffed it, saying the radical group had no presence in Bangladesh though officials said JMB was ideologically inclined to the foreign Islamist group.
Bangladesh has seen a spate of gruesome attacks on secular activists, religious minorities, bloggers and foreigners, many of whom have been hacked to death with machetes.
The country had launched a massive crackdown on militants specially after the July 1 Dhaka terror attack in 2016 in which 22 people, including an Indian, were killed.
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