Complex sentence: The writer always admitted that the killer was not based on anyone he knew however in Milan in 2004 he said there was a hint of truth in his writings, although did not disclose any further information on the subject.
Split into simpler sentences: The writer always admitted that the killer was not based on anyone he knew. However in Milan in 2004, he said there was a hint of truth in his writings, although did not disclose any further information on the subject.