Los Angeles:  Police investigating the shooting of students at Salvador B. Castro Middle School said the handgun that was carried into a classroom appears to have fired a single round from inside a backpack.

The gunfire erupted in a full classroom shortly after the morning bell Thursday and sent students fleeing. The bullet struck a 15-year-old boy in the temple and a 15-year old girl in the left wrist. Two other students and a teacher suffered minor injuries.

"The physical evidence seems to support that it was discharged from within the backpack," LAPD Deputy Chief Robert Arcos said Friday morning.

Investigators believe only two students were struck by the bullet, Arcos said.

"We believe the trajectory of that round travelled through a through-and-through wound first and then struck the other victim in the face," he said.

A 12-year-old girl was taken into custody and a semi-automatic pistol - which was unregistered - was recovered at the scene. The girl has been booked on suspicion of negligent discharge of a firearm and bringing a loaded firearm onto a school campus, Arcos said.

Police are still trying to determine how the girl obtained the weapon.

"That's still the big question mark for us," Arcos said. "We are getting cooperation from the family."

Arcos said that the 12-year-old has an attorney and is not talking to investigators.

"We would love to be able to talk to her more fully in an interview and just get to the intent and motive," Arcos said. "There's a lot of things I'm sure are going through her mind right now - she's only 12 years old. Hopefully we'll have an opportunity again to talk to her."

The girl's name has not been released because she is a minor. Television news footage Thursday showed a young girl with long hair, jeans and a blue Sal Castro sweatshirt being escorted to a police cruiser in handcuffs.

On Friday morning, anxious parents accompanied their children to the school as classes resumed.

Guadalupe Segura placed her hand on her heart as she watched her 13-year-old daughter, Jazmine, walk into the Westlake middle school, along with dozens of other students.

"I'm bringing her here to the school alive, and I don't know what will happen to her between now and when she comes home," Segura said. "Anything can happen, even at schools."

Although classes resumed as normal, some students arriving at the school Friday morning said they weren't ready to come back.

"I'm kind of afraid for my safety," said Oswaldo Gonzalez, 11, a sixth-grader at the middle school. "My parents told me to try and stay safe."

Maria Serrano reluctantly dropped off her 12-year-old daughter at school. She had been in Calabasas when she heard about the shooting, describing it as a "dramatic day."

"I told her if you want to come to school, I'll support that, but if you don't, it's OK," Serrano said. "She had nightmares and kept waking up because of what happened."

Noe Garcia, 13, an eighth-grader at the middle school, said he was still a little shaken from the shooting but felt well enough to come back.

"I'm worried about the kids who got shot," he said. "I hope they're OK."

At least one student who was in the classroom when the shooting occurred told a reporter Thursday that he thought the gunfire was unintentional.

"Someone decided to bring a gun. I guess someone was accidentally playing around with it," said Benjamin, a 12-year-old seventh-grader whose guardian asked that his last name not be used. "They thought it was a fake gun."

None of the identities of those who were injured have been released. In addition to the two 15-year-olds, they were described as a 30-year-old woman, an 11-year-old boy and a 12-year-old girl.

At a news conference at Los Angles County-USC Medical Center, doctors said they had treated four students with gunshot wounds. Two of those injuries were minor graze wounds and the students were released, officials said. Police and fire officials have said that only the two 15-year-olds suffered gunshot wounds and that the other three injuries were abrasions, some caused by glass.

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