A Snohomish High School freshman is listed in critical condition after another girl stabbed her and a friend in a school bathroom Monday morning.

The suspect, a girl who is a sophomore at the school, was taken into custody. KIRO 7 Eyewitness News video showed police putting her in a patrol car Monday afternoon. She was taken to the Denney Juvenile Justice Center in Everett.

The stabbing happened at about 7:25 a.m., a school district spokeswoman said.

Police said the sophomore attacked two freshmen girls, stabbing one in the chest and neck. The other victim, who was stabbed in the arm, was later released from the hospital.

"At first, we thought it was a drill. Then we started freaking out because we found out it wasn't a drill," said Brandon Wiggins, a Snohomish High School student.

"It's kind of a surprise because the school is really nice," said Isabelle Anana, a student who was in choir when the school went into lockdown.

The school district sent out an alert to parents, said KIRO 7 Eyewitness News reporter Lee Stoll. Some parents arrived at school to take their children home.

Police said investigators don't know what led up to the attack, but that they're looking into possible Facebook postings that the suspect made a few days ago, threatening to harm herself or someone else.

Police said the suspect, who they said could be charged with attempted murder, may not have had an intended target.

"It's hard to say, but right now … it's leaning on the random side," said Snohomish Police Chief John Shelton.

A hospital spokesperson said the victim underwent six hours of surgery.

The grandfather of one of the victims said the two are like sisters. He told Stoll that his granddaughter ran for help and then went back to try to save her friend.