Investigators in Australia believe some of the deadly wildfires ravaging dry southeastern bushland may have been set, a conclusion prompting Australia’s prime minister to call such acts "mass murder." Officials in Victoria state have launched arson investigations into some of the blazes, which have killed at least 166 people, decimated massive spans of land and left thousands of people homeless. “I think it’s important that the nation braces itself for more bad news,” said Australian Prime Minister Kevin Rudd, tearing up at one point during a TV interview on Monday. “This is a little horror which few of us anticipated.” News that some fires may have been deliberately set brought a note of disgust from the prime minister