SACRAMENTO, CA (AP) — California fire investigators have officially concluded that the deadliest U.S. wildfire in a century was caused by Pacific Gas & Electric Corp. power lines. State fire officials said transmission lines owned and operated by the San Francisco-based utility started the November 8 fire that wiped out nearly 15,000 homes in the town of Paradise. Many of those killed were elderly or disabled. The oldest was 99. al Fire deputy director Mike Mohler said investigators determined there were violations of law. Cal Fire did not release its full investigative report, saying it had been forwarded to the Butte County district attorney’s office, which is considering criminal charges against the utility.