The 67-year-old Ivan Bartulovic died on Thursday night after unknown perpetrators beat him in the outskirts of Banja Luka, Cordas said.
Cordas criticised the entity's interior ministry and media for keeping silent about the murder of the Croat returnee.
He also expressed hope that the perpetrators would be found and punished and that the murder would not discourage other Croats wishing to return to their pre-war homes in the northwestern Bosnian city.
Political parties representing local Croats condemned the incident and said that it was yet another proof that it was necessary to reform the police and abolish the Serb entity's police force.