The man who broke into George Harrison's suburban London estate last December and repeatedly stabbed the former Beatle was found innocent by reason of insanity in an Oxford, England, courtroom today. The verdict was reached after psychiatrists had testified that the assailant, Michael Abram, 34, believed that he was possessed by the spirit of Harrison. Judge Michael Astill then sentenced Abram to a mental hospital indefinitely. Yesterday, Harrison informed the court of his life-or-death struggle when Abram stabbed him in the chest with a seven-inch knife, puncturing his lung. "I thought I was dying," Harrison, 57, testified. "I vividly remember a deliberate thrust of a knife, and I could feel the blood entering my mouth and hear my breath exhaling from the wound." Earlier in today's proceedings, three psychiatrists told the court that Abram has suffered from severe paranoid schizophrenia for a decade. One doctor added that Abram thought all four members of the Beatles were practitioners of black magic.