The Supreme Court granted the prosecution's appeal and changed the Karlovac County Court's acquittal. The county court had acquitted Hrastov on three occasions.
A panel of judges found that Hrastov was guilty of war crimes against prisoners of war and that, contrary to his claims, he did not act in self-defence and that he shot at enemy soldiers who had surrendered, killing 13 and seriously wounding two.
This, the sixth sentence against Hrastov, is not final. He can appeal to the Supreme Court again.
Hrastov was not present at the sentencing. He remains free because he was given a sentence of under five years.
Defence attorney Kresimir Vilajtovic said the sentence left many possibilities for appeal.
Prosecutor Jasmina Dolmagic said she was glad the prosecution's arguments were granted and that the trial court sentence was changed but said she would appeal the length of the punishment.
Victims' representative Luka Susak was pleased with the sentence too.
Hrastov has served more than half the sentence, spending a little under two years and two months in custody on two occasions.