Diana Sue Sylvester had been living in San Francisco only six months when she was raped and killed in the Sunset District after walking home from work at UCSF, three days before Christmas in 1972. On Friday, San Francisco police said DNA evidence and a computer search of sex offender records finally had led them to a suspect. John Puckett, 72, a retired carpet installer living in Stockton, was arrested at a trailer he shared with his wife, Marlene, and is expected to be arraigned next week on murder charges in the slaying of the 25-year-old nurse. "Even though he's...