A student at a California high school is accused of killing two others, on his sixteenth birthday. Investigators search for a motive and we hear from two sisters who saw it all. Impeachment proceedings resume on Capitol Hill with testimony from the former ambassador to Ukraine, who says the president's lawyer plotted to get rid of her. A death row inmate in Texas whose case gained national attention could learn today whether the U.S. Supreme Court will hear his case. A manhunt is intensifying around Roanoke, Virginia, for an AWOL marine accused of murder. Venice, Italy -- already dealing with catastrophic flooding -- is bracing for a high tide today that could reach nearly twice the normal level.