I just heard about his passing this morning.
If you're trying to place the name, or not into metal, Jeff was a founding member & guitarist of punk-inspired thrash metal band, Slayer contributing both lyrically & musically to every Slayer album in existence. He had some major medical problems in 2011 & managed to recover by early last year. His death was not related AFAIK (I heard liver failure). He was a musical genius, writing the music for nearly every one of the band's best tracks. His dueling solos with Kerry King were extremely technical & always walking the line of chaos.
Rest in peace Jeff, your contributions to music will not be forgotten.
1/31/64 - 5/2/13