A 15-year-old girl was arrested after allegedly making threats against a high school in Fullerton on an Instagram Live, police announced Thursday.

Troy High School officials alerted police on Wednesday night that a threat had been made against them on the social media platform. The school is adjacent to Cal State Fullerton.

A student told authorities that he or she was on a group chat with other students when an unknown user started messaging the group saying there would be violence against the school the next day.

Fullerton Police School Resource officers and the Fullerton Joint Union High School District vetted the threat and concluded that it was not credible, but Fullerton Police Department officials arrested a teen on suspicion of making criminal threats and obstructing or delaying an investigation.

Police did not elaborate on what kind of threat was made and did not release any more information on the teen.

Authorities said the threat was taken seriously and commended the “courageous” student who came alerted officials of the threat.

The social media threat was discovered a day before five people were injured in a school shooting in the Westlake district of Los Angeles.

A 12-year-old girl was taken into custody in connection with that shooting at Sal Castro Middle School.