Bartetzko left the HVO in April 1994, citing the "very cruel scenes, which could be described as atrocities" he witnessed being committed by his fellow HVO fighters. He subsequently volunteered to fight with the Croatian Army and participated in Operation Mistral 2 in the closing stages of the Bosnian War. Upon returning to Germany, Bartetzko was arrested for allegedly stealing a woman's handbag. Following the outbreak of the Kosovo War in 1998, Bartetzko travelled to Tirana, Albania. He subsequently crossed the Albanian–Yugoslav border into Kosovo and joined the Kosovo Liberation Army (KLA) as a volunteer. During his time with the KLA, he assumed the "nom de guerre" Shaban, the eighth month of the Islamic calendar.