The arrested terrorist whose real name is Nahid Hossain and he identified himself as Jihadi John has been arrested from Tejgaon area of Dhaka on Tuesday.
"We detained him from (Dhaka's) Tejgaon area last night after tracking him down as one who has been issuing the death threats on the internet for the past several months in the name of IS (but) we believe he is actually linked to Jamaat," a police spokesman told PTI.
"We believe sometimes this Nahid described him as an operative of IS and sometimes the Ansarullah Bangla Team," he said.
His arrest has come a day after a court in Dhaka indicted four suspected ISIS operatives on charges of hatching plots to topple Prime Minister Sheikh Hasina's government.
Bangladesh has always denied ISIS presence in the country. But the group recently said that it has appointed a "regional leader" in Bangladesh.
"There's no organisational presence of something like the IS in Bangladesh," said Home Minister Asaduzzaman Khan Kamal.
"Those who claim to be ISIS are all 'fruits of the same tree' - namely Jamaat, Ansarullah Bangla and JMB," he added.