The teenage gunman arrested after a massacre that killed 10 people and wounded 13 at his school outside Houston confessed following a 15-minute firefight with authorities, court documents say.  His statement left why he laid waste to Santa Fe High School a mystery, but a mother of one victim said her daughter had rejected his advances a week before the attack.

          Dimitrios Pagourtzis, a junior at the school, was taken into custody after he collapsed in front of an art lab, according to a probable-cause affidavit filed in court.  The teenager waived his Miranda rights and "admitted to shooting multiple people inside the school," the document said. More details emerged Saturday about what happened before that in the classrooms and halls of the school.  

          The attack began with a shotgun blast through the door of the art classroom, wittnessed said.  That sent panicked students to the entryway to keep the shooter outside.  The shooter was wearing a trench coat and carrying a revolver and sawed-off shotgun.  The gunman fired again through the wooden door, killing his first victim who was shot in the chest.  The gunman killed seven more students and two teachers before exchanging gunfire with police and surrendering.

          A students mother said her daughter had recently ignored the romantic advances of the 17-year-old, a possible motive for the state's deadliest school shooting since Charles Whitman, the University of Texas Tower sniper, killed a total of 17 people in 1966.