Keith Haring used many Christian and Biblical motifs in his grafitti-like art. Some art critics believe that Haring was criticizing how religion takes hostage of one's life. Others see a more complex interplay of biographical reflection (Haring could be obsessive, whether as a sort of Jesus freak in his high school years, or, as a devotee to drugs, rock-and-roll and homosexuality, according to some friends), irony, and fate. Julia Gruen, Haring's studio assistant, observed that religion was "omnipresent" in his work. "He was such an extraordinary optimist, and had such an embrace of life. One can't help but think that there's something very spirtually evolved and informed by that." Haring's work has a tortured quality within its joy that reminds one of the artist Francis Bacon. Haring died of AIDS in 1990.