"The court left the sentence unchanged. It comes into force starting today," a spokesman for the court said.
On May 21, 2002, Alexei Anikin, Alexei Britov and Sergei Malyutin hurled Molotov cocktails through the windows of General Gamov's apartment in the regional capital of Yuzhno-Sakhalinsk. Gamov died of his injuries a week later.
The men, who were only arrested over three years later, were sentenced to four years in prison for manslaughter on November 17, 2006. They were also each ordered to pay 400,000 rubles ($16,360) in damages to Gamov's widow and son.
The defense then appealed for milder sentences in 2007, but the Supreme Court ruled against the plea, leaving the previous sentence in force.
Gamov's death was believed to have been linked to his crackdown on poachers involved in the illegal fishing trade with Japan, China, and South Korea.
