PHOENIX - Tensions are high at a Phoenix high school after a threat of another shooting.
The latest threat was made against Carl Hayden High School earlier this week.
Police say some kind of a note or message was found on campus that said a shooting would take place on Friday.
School officials immediately contacted police and an investigation was started.
News of the threat spread quickly through social media, including Twitter.
One student wrote it wouldn't surprise her, while another tweeted that she's scared and doesn't want to go to school.
"It's scary because supposedly they were going to do it during an assembly during the national anthem. So it's pretty scary not knowing if it's going to happen, if it's true or not," student Laura Buenda told ABC15.
Phoenix police Sgt. Steve Martos said extra patrol officers will be on campus Friday. Investigators are trying to figure out who is behind the threat.
One student's mother said she's worried.
"My son and my daughter just told me that they found a letter in the bathroom... that they were going to kill somebody here, so I don't know. I am worried about it," said Olga Gonzalez.
The Phoenix Unified School District says it will contact parents either through a letter, phone call or text message about the threat.
A school official wants parents to be assured they are on top of the threat.