MANATEE COUNTY, Fla. (WFLA) — Students at Parrish Community High School were evacuated Tuesday following two bomb threats submitted via a mobile app.

Authorities said the threats were submitted via FortifyFL, a suspicious activity reporting tool that allows users to instantly relay information to the appropriate law enforcement agency. A bomb was said to go off at 10:15 a.m. while students were in class.

As a result, the school was evacuated and brought to the outdoor bleachers as authorities cleared the building. The incident marked the fourth such threat the school received since Feb. 1.

“Been a lot of threats and a lot of false alarms. For example this one a lot of kids were freaking out either way,” said freshman Jarred Furst.

Furst’s mother rushed to the school to pick up her son.

“Part of it is wondering if they are desensitized and now you know they’ve had four days at the same threat, so what happens if this is a real incident?” said Jamie Furst.

Manatee County Sheriff Rick Wells said his agency is working with the FBI. He says these have been non-credible threats. He’s also asking parents to talk with their kids to make sure they’re not involved.

“These threats have come through the FortifyFl app. As you know that’s all about anonymity,” Sheriff Wells said. “The problem we’re having is that when they use the app, the host site may not be in the state of Florida.”

Wells said his deputies located an IP address, similar to a digital footprint, that passed through a server in California.

“At one point we believe [the suspect] used a different VPN that you can get online and that IP address was pushed through a host site in Romania,” Wells said. “We’re currently working with the FBI to help us out in Romania and also in California.”

“We must take action and we must take each threat credibly,” Superintendent Cynthia Saunders said.

“I’m concerned with the amount of time this has taken away from our student’s education,” said Principal Craig Little. “Please know that I am committed to getting to the bottom of this and finding out who the source is.”

“When we find who is responsible, we will arrest them,” Wells said. “We will take them to jail.”

Crime Stoppers of Manatee County is offering $500 reward for a tip that leads to arrest.