In the attack, Brkovic sustained serious injuries to his head and leg.
The police have not yet identified any suspects.
"Although police inspectors have collected some traces leading to possible perpetrators, this is still insufficient to arrest anybody," a police source was quoted by the media as saying.
The police, however, do not lose hope that "the case will soon be solved."
The writer believes that possible assassins are from the Montenegrin underworld who recognised themselves in characters of his latest novel "Ljubavnik Duklje (Lover of Duklja)".