CHICAGO – A man who police suspect strangled a 16-year-old suburban Chicago girl in 1976 may have killed as many as a dozen young women and plotted to kill others before he died during a fatal knife attack on a teenage boy, a detective investigating the case said Tuesday. “When we start digging to see common threads [in missing persons cases], there are nine that we’re aware of and that number could go up to 12,” Lisle Police Detective Chris Loudon said of his investigation into Bruce Lindahl, who has been linked by DNA evidence to the 1976 slaying of Pamela Maurer. That total raises the chilling prospect that from the 1970s until his death in 1981, Lindahl may have been abducting, raping and killing women and girls without raising suspicions in various suburban police departments.