ROUND ROCK, Texas (KXAN) — Four students were temporarily detained and Cedar Ridge High School was placed on lockdown due to a report of a possible weapon on campus, according to Cedar Ridge Principal Jiae Kim and the Round Rock Police Department.

The lockdown was lifted at 10:47 a.m. and no gun was found.

Round Rock police said it had concluded its investigation at 4:34 p.m. Thursday. It tweeted, “The two witnesses that claimed they saw a gun later admitted that they were mistaken. Four students believed to be involved were questioned and cleared.”

A letter was sent from Round Rock ISD to parents of students at Cedar Ridge High School notifying them of the lockdown. The letter stated the lockdown was put in place at 10:05 a.m.

Dear Cedar Ridge parents, guardians, and staff,

I am writing to inform you that we placed our school on lockdown at approximately 10:05 a.m as our campus and law enforcement investigate reports of a possible weapon on campus. 

Students and staff will remain in their classrooms and no one will be allowed to enter or leave the building as we investigate this report. I will share updates with you as more information is available. 

Thank you,

Jiae Kim, Principal

A subsequent email from Kim stated the lockdown was lifted and confirmed that no gun was found at the school.

Round Rock police says it was first alerted to the report of a possible gun on campus at 10:04 a.m.