A Russian regional court on Monday convicted four teenagers of burning a man to death in the eternal flame of their town's World War II memorial.

The Vladimir Regional Court gave prison sentences of 16 to 18 years to three 19-year-old defendants, while a 15-year-old defendant was sentenced to a juvenile detention center for nine years, court spokesman Vladimir Ganenko said.

The victim, 25-year-old Alexei Denisov, came upon the teenagers while walking home on the night of Jan. 1 in the town of Kolchugino, about 80 miles northeast of Moscow.

The teenagers, who had been drinking, were accused of beating Denisov unconscious and throwing him face-first into the town's eternal flame, part of a memorial to Soviet soldiers killed in the Second World War.

"This was a brutal, cruel, conscious, group murder, and of course it deserves a severe punishment," Denisov's mother, Olga, told the television station NTV.

The defendants — 19-year-olds Alexander Andreyev, Mikhail Danilov, Nikolai Kuragin and 15-year-old Alexei Goryachev — intend to appeal the court's decision, Ganenko said.