Florida gunman had extra ammo at school, fired for three minutes

The teenager accused of using a semi-automatic rifle to kill 17 people at a Florida high school confessed to carrying out one of the nation's deadliest school shootings and carried extra ammunition in his backpack, according to a sheriff's department report released on Friday. Nikolas Cruz told investigators that he shot students in the hallways and on the grounds of Marjory Stoneman Douglas High School in Parkland, north of Miami, the report from the Broward County Sheriff's Office said.

Cruz said he brought more loaded magazines to the school and kept them in the backpack until he got on campus. The gunman fired into five classrooms -- four on the first floor of the school and one on the second floor, Sheriff Scott Israel said.

The shooting lasted for three minutes. When he was done firing, the assailant went to the third floor and

dropped his AR-15 rifle and the backpack containing the ammunition. He then ran out of the building and attempted to blend in with fleeing students, Israel said.

After the rampage, the suspect headed to a Wal-Mart and bought a drink at a Subway restaurant before walking

to a McDonald's. He was taken into custody about 40 minutes after leaving the McDonald's, the sheriff said.

A day after the attack, a fuller portrait emerged of the shooter, a loner who had worked at a dollar store, joined the school's ROTC program and posted photos of weapons on Instagram. At least one student said classmates joked that Cruz would "be the one to shoot up the school." The 19-year-old orphan whose mother died last year was charged with murder today in the assault that devastated this sleepy community on the edge of the Everglades. It was the nation's deadliest school attack since a gunman targeted an elementary school in Newtown, Connecticut, more than five years ago.

Meanwhile, students struggled to describe the violence that ripped through their classrooms just before the school day ended.

Catarina Linden, a 16-yearold sophomore, said she was in an advanced math class Wednesday when the gunfire began."He shot the girl next to me," she said, adding that when she finally was able to leave the classroom, the air was foggy with gun smoke. "I stepped on so many shell casings. There were bodies on the ground, and there was blood everywhere."