Two more bodies were found Tuesday, raising the death toll to 15 after the runaway train carrying crude oil slipped from its moorings early Saturday, speeded almost 7 miles down a steep grade, derailed and exploded in the town of Lac-Mégantic. About three dozen other people remained unaccounted for. Authorities said the cause of the incident still wasn't known, but they contested the assertion of Ed Burkhardt, chairman of [Rail World,] the parent company of Montreal, Maine & Atlantic, the railway that operated the train, that "we have evidence" that it had been tampered with.