It was a somber and emotional day for students at Corona Del Sol High School.
A fellow classmate brought a gun to school and took his own life Tuesday morning on the school's campus.
It's a situation that is forcing many parents to confront the idea of teen suicide, and many more are taking action by calling experts for advice.
18-year-old Marcus Wheeler was a top athlete, a star cross country runner. Police are now trying to determine why he came to his high school armed with a gun and prepared to commit suicide.
"They just ran in and told everybody to get in a room, and the lock down things started," said Azalea Lopez.
Lopez was in the school's gym; the incident happened right outside around 8:50 in the morning.
"The security guard ran in and told us everyone needs to get in the room, someone has a gun, it was really frantic," she said.
Tempe Police confirmed that Wheeler sent a tweet minutes before saying "There is going to be a suicide in the school right now."
The school resource officer was alerted and tracked down the student; she tried to talk him out of it.
"This definitely had an impact on the first responder, this call for service, I can only imagine is going to live with the officer who is a mother for the rest of her entire career," said Lt. Scott Smith.
After the shooting, the school went into lock down for about 90 minutes. Parents rushed to the school, waiting to pick up their kids.
By 10:15 in the morning the school released more than 2,500 students.
"You don't ever want to come to the school you know they say somebody has a gun, it's the worst fear," said Evette Teran.
Many parents got the news from their kids via text message.
"She is really shaken, and I am really nervous myself because she is my only girl, and I want to make sure that she is ok," said William Collins.