Catholic priest Mile Ivancic from the Zavalje parish near Bihac in Bosnia and Herzegovina was killed by three minors whose only motive was gain, local media said on Tuesday.
Federation TV reported that two Bosniaks and one Croat were suspected of the murder, aged 15, 16, and 17.
They were allegedly among the persons the police arrested on Monday.
Citing unnamed police sources, Sarajevo's Dnevni Avaz said one of the murderers was the son of the woman who cleaned the rectory and found the body.
Police are expected to release official information about the investigation in the afternoon. Under the law, they cannot reveal the suspects' names if they are underage.