"We have announced a bounty amounting Taka 1 lakh (USD 1250) for information about whereabouts of the culprits," Brahmanbaria's police superintendent Mizanur Rahman told PTI.
He added that 78 suspected attackers were so far arrested after detailed investigations but Hindu leaders and civil society feared that several masterminds remained beyond the ambit of law enforcement agencies.
The development came amid speculation that the attacks on Hindu temples and households were staged at Nasirnagar area of the district as part of a conflict between two influential groups of ruling Awami League.
Authorities have launched an intensified campaign to track down the culprits after home minister Asaduzzaman Khan warned that none of the attackers will be spared.
More From This Section
Prime Minister Sheikh Hasina had also urged the people to stand with religious minorities.
"As a Muslim-majority country it is the moral responsibility of all of us to take care of the minorities," she told a conference at her office.
She added: "You have to remain careful so that no such incidents, which are taking place sporadically in different parts of the country, take place anywhere in the country."
The Hindu community leaders and civil society activists staged a series of protests in the capital and other major cities blasting the administration for failure to protect the minority community.
The statutory National Human Rights Commission (NHRC) had said that the attacks on Hindu temples and households were carried out under a well orchestrated plan.
Hindu community leaders earlier said the attacks were carried out to evict Hindus from their own land creating an atmosphere of fear.