Complex sentence: After Barış Manço's death in 1999, the band began working with Cem Karaca and after Cem Karaca passed away (2004), Bahadır Akkuzu took over the vocals.
Split into simpler sentences: After Barış Manço's death in 1999, the band began working with Cem Karaca. After Cem Karaca's death in 2004, Bahadır Akkuzu took over the vocals.