The police had offered cash bounties of about $25,000 this month for information leading to the arrest of Mr. Chowdhury and for another militant, Syed Mohammad Ziaul Haque, who was suspected of being involved in recent killings of secular writers.

Mr. Chowdhury’s name was on a list of 10 high-value suspects released by the Bangladeshi authorities last month after the Holey Artisan Bakery attack, an 11-hour siege carried out by five militants who were eventually killed by soldiers. Analysts said Mr. Chowdhury and two other Bangladeshi expatriates on that list could have been acting as links between local and international extremist groups.

The bakery siege was the most deadly in a series of violent attacks carried out by Islamist militants in Bangladesh over the past several years. The frequency of those attacks has increased in recent months.

Officials said they suspected that Mr. Chowdhury was also behind a July 7 bombing at Bangladesh’s largest prayer gathering for the Eid al-Fitr holiday, which killed four people: two police officers, a civilian and a militant.

Home Minister Asaduzzaman Khan said Saturday in televised remarks to reporters that the identities of the two militants killed with Mr. Chowdhury would be released after an investigation, but that one of them appeared to be Mr. Chowdhury’s right-hand man.

It was not clear whether either of them was on the list of high-value suspects released last month.

“We think Tamim Chowdhury’s chapter has ended here,” Mr. Khan said. “We will be able to catch the rest of the militants soon.”