Mancha’s local unit chief Debashish Debu announced the protest programme minutes after the killing on Tuesday.
Several machete-wielding men hacked 30-year-old Das to death in the morning when he was going to the city.
Das used to write on ‘Mukto-mona’ (free thinkers), a blog site propagating rationalism and opposing fundamentalism, that was started by Avijit Roy who was killed in a similar attack in February in Dhaka.
“We’ll observe an eight-hour strike in Sylhet [on Tuesday] from 6am,” Debu announced.
Another blog activist Oyashiqur Rahman, who was killed in similar fashion in Dhaka in March, was also a Mancha activist.
The Mancha, pressing for banning Islamist parties and maximum penalty for war crimes convicts, took out a procession in Dhaka on Tuesday.
It blamed the government’s “failure” for the killings.
“The latest killing proves the government’s indifference and failure to tackle militancy and terrorism,” Mancha spokesperson Imran H Sarkar said in a statement.
“Such attacks on free-thinkers are results of the government’s failure.”
Police suspect extremists for the killing of bloggers, all of whom were hacked to death.
Earlier this month, al-Qaeda's Indian offshoot claimed responsibilities for the killings of secular bloggers in Bangladesh it dubbed as 'blasphemers'.