In what has become a recurring event, another threatening note has been found at Highland Park High School in University Park -- this time in a stairwell.
On Wednesday, students were again dismissed early after several .22-caliber bullets were found in a different boys bathroom.
With restroom access now restricted, the written bomb threat found Thursday was located in a stairwell.
Police said the note was very similar in writing and content to the ones found in the bathroom.
The school said in a note to parents that they do not believe the threat is credible and that students would not be dismissed early.
The Highland Park school district said it plans to continue to have an added police presence until it feels it is no longer needed. The district is also looking at adding security wands.
"I'm not ready to make that call yet," Superintendent Dawson Orr said. "That does fundamentally change the nature of how kids enter into school every day. Right now, we [have] a very heavy police presence. We think the wands would be a backup -- it's something we do need to evaluate."
So far, no arrests have been made in connection with any of the threats. Officials said if the threats are connected, the person responsible will face felony charges.
The FBI is testing the bullets found Wednesday for DNA in an attempt to trace from where they came.
A $7,500 reward is being offered for information that leads to an arrest in the case.
The school released to parents the following note about Thursday's incident:
"Another threatening note was found at HPHS. It was found by a UP police officer at the top of a stairwell. We have no reason to believe that it is a credible threat, and we are continuing with the school day.
FBI agents and armed police officers are on campus working with school officials to question students.
We believe it is imperative that we not give in to repeated threats. We acknowledge the stress and anxiety that this has caused for our students, staff and families. Our top priority is to keep everyone on our campus safe and secure. The building has been repeatedly searched and determined to be safe. Armed police officers have been on campus all day. We are aggressively pursuing resolution in this series of highly disruptive events.
For those parents who wish to pick up their children, please contact the attendance office to do so. Standard attendance policies will apply.
HPISD will continue to update parents, students and staff through its emergency text-message system, email, and posts on the district website."
NBC 5's Ray Villeda contributed to this report.