In 1912, when the Serbian army entered the Kosovo Vilayet, Serbian soldiers, both voluntarily and under orders, began killing boys, raping girls, stabbing unarmed men, burning women and children in haystacks, strangling boys to death, and stabbing boys to death with bayonets. The bodies were then mutilated by Serbian soldiers. Serbian soldiers also burned all the houses and stole all the livestock, sheep, and cows. Serbian soldiers would also break into the homes of Albanian civilians and beat the husbands until they told them where the girls were hiding, and then the Serbs would rape them.

These crimes included:

Stabbing babies in cradles, raping girls, killing boys with bayonets, stabbing unarmed Albanian men, stabbing pregnant women and killing fetuses, burning the elderly and civilians alive in their homes after tricking them into coming out, locking Albanian civilians in mosques and blowing them up with grenades, beating Albanians to death with wood to save ammunition, allowing Albanian wounded to starve to death in hospitals, burning Albanian women and children tied to hay, throwing babies into the fire, etc.

Sources:

Leo Freundlich — Albanian Golgotha ​​(1913)
A first-hand account and compilation of reports of Serbian massacres, expulsions, torture, and abuse of Albanian civilians during the Serbian invasion of Kosovo and neighboring regions in 1912–1913.

Reports by Leon Trotsky
Leon Trotsky, then a journalist, documented the crimes committed against Albanians during the Balkan Wars, including executions and excessive violence, in reports that circulated in European newspapers in 1912–1913.

Kosta Novaković (Serbian Social Democratic Opposition)
Novaković, a Serbian socialist and eyewitness, reported exceptionally high casualty figures among Albanians at the time, including massacres and expulsions by Serbian forces.