The UN War Crimes Tribunal in The Hague has convicted the first Kosovan Albanian of crimes carried out during the conflict with the Serbs in 1998.
Haradin Bala has been sent to prison for 13 years for torturing and murdering prisoners at a camp run by the Kosovan Liberation Army.
His co-accused, Isak Musliu, and alleged commander Fatmir Limaj, were cleared of all charges and ordered to be freed by the court.
The presiding judge ruled that there was not enough evidence to link them to the camps or to the murders in question.
34 year old Limaj is considered a hero by some in Kosovo. He was a senior figure in the KLA and a key figure in the Democratic Party of Kosovo, now the main opposition in the UN-run province.
Before the result was announced, thousands of people marched through the streets in support of the three men.
Once the verdict was known, celebratory gunfire and car horns were heard on the streets of the capital, Pristina.