On Sunday, the Ministry of Home Affairs urged the citizens to share with law keepers or nearby police stations if they have any information on one Mostafizur Rahman.
Islam, organiser of Bangladesh Centre for Workers Solidarity (BCWS) and President of a labour union of an Ashulia unit, disappeared on Apr 4 last year. His body was found two days later in Tangail.
A media statement from the ministry on Monday said the informer's identity would not be made public.
It said Mostafizur Rahman, son of Md Shamser Biswas, hailed from Magura Sripur Thana's Kadirparh.
After he was buried as an 'unidentified person', Islam’s family had identified him from his picture published in a newspaper. They reburied him in his village home.
On the day he disappeared, Islam was trying to resolve a labour impasse at factories that stitch shirts for Tommy Hilfiger, American Eagle and other global brands.
Various international quarters have been pressing the government to bring his killers to justice.
During her 2012 Dhaka visit, the then US Secretary of State Hillary Clinton warned that Bangladesh's failure to probe the murder would send "a wrong signal" to the American buyers.