CPJ is seeking to determine whether Grodnikov, 66, was murdered in retaliation for his journalistic work.
Authorities have harassed Narodnaya Volya in retaliation for its criticism of President Aleksandr Lukashenko. State-run kiosks are not permitted to sell the newspaper and authorities recently ended its printing contract, forcing it to use a printer in the neighboring Russian city of Smolensk.
"We are shocked and saddened by the death of Vasily Grodnikov, " CPJ Executive Director Ann Cooper said. " We call on Belarusian authorities to investigate this killing and prosecute those behind it."
Grodnikov's brother, Nikolai Grodnikov, said Wednesday the journalist was murdered because of his work for Narodnaya Volya, Agence France-Presse reported. Nikolai said his brother had survived an attack in January, but he gave no details of any assault. Narodnaya Volya editor-in-chief Yosif Seredich said on Tuesday that Grodnikov wrote mostly about social issues, and had no links to the authorities or the opposition, the independent news agency Belapan reported.
Nikolai Grodnikov said, "There was a lot of blood on the walls, the floor, the window... Everything in the house was turned over." The journalist's niece, Natalya Grodnikov, added that there were no signs of robbery or forced entry.
The Interior Ministry for the Minsk region said Wednesday that there was no sign of a struggle or a robbery in the apartment and that Grodnikov had died of a stroke, the independent Moscow daily Gazeta reported. However, an autopsy at the Minsk Regional Clinical Hospital concluded on Wednesday that the cause of death was head trauma. A medical report is being sent to the Minsk regional prosecutor's office, which is investigating the death, Belapan reported.
Another Belarusian journalist, Veronika Cherkasova, 44, was murdered a year ago while working for the Minsk-based opposition newspaper Solidarnost. Her murder remains unsolved and journalists have criticized authorities for focusing on her teenage son as a suspect rather than investigating work-related motives for her killing.