Mayhem's lineup changed because of the murder of which founder of the early Norwegian black metal scene?
Øystein Aarseth
Title: Euronymous
Passage: Øystein Aarseth (] ; 22 March 1968 – 10 August 1993), who went by the pseudonym Euronymous, was a Norwegian guitarist.  Euronymous was a founder of and central figure in the early Norwegian black metal scene.  He was a co-founder of the Norwegian black metal band Mayhem.  He was also founder and owner of the extreme metal record label Deathlike Silence Productions and record shop Helvete.
Title: Darkthrone
Passage: Darkthrone is a Norwegian heavy metal band.  It formed in 1986 as a death metal band under the name Black Death.  In 1991, the band embraced a black metal style influenced by Bathory and Celtic Frost and became one of the leading bands in the Norwegian black metal scene.  Their first three black metal albums—"A Blaze in the Northern Sky", "Under a Funeral Moon" and "Transilvanian Hunger" (sometimes dubbed the "Unholy Trinity") — are considered the peak of the band's career and to be among the most influential albums in the genre.  For most of this time, Darkthrone has been a duo of Nocturno Culto and Fenriz, who have sought to remain outside the music mainstream.  Since 2006, their work has strayed from the traditional black metal style and incorporated more elements of traditional heavy metal, speed metal and punk rock, being likened to Motörhead.
Title: Mayhem (band)
Passage: Mayhem is a Norwegian black metal band formed in 1984 in Oslo.  They were one of the founders of the Norwegian black metal scene and their music has strongly influenced the black metal genre.  Mayhem's early career was highly controversial, primarily due to their notorious live performances, the 1991 suicide of vocalist Per Yngve Ohlin ("Dead") and the 1993 murder of guitarist Øystein Aarseth ("Euronymous") by former member Varg Vikernes ("Count Grishnackh"), of Burzum.
Euronymous Mayhem (band)