MINNEAPOLIS (WCCO) — Back to school is the time the FBI warns they see an increase in hoax threats against schools.

Law enforcement takes every threat seriously and investigates each one to determine if it’s credible or a prank. Every time there’s an investigation, it drains resources, costs taxpayers dollars and can also land the person making the threat in jail.

Orono High School in Orono, Minnesota went on lockdown near the end of last school year. Local and federal law enforcement surrounded the building after a threat to shoot up the school posted on Twitter.

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“It required a substantial response and effort to determine that it wasn’t a real threat,” FBI Assistant Special Agent Joe Rivers said.

Rivers said the ease of posting on social media has increased the number of school hoax threats nationwide, and he says students are often behind them.

“Young adults who make the threats really don’t have a sense for what the ramifications are for doing so, or what the long-term implications of that are,” Rivers said.

The FBI and other law enforcement agencies investigate every tip and many cases are prosecuted.

In 2015, authorities extradited a Houston, Texas, teen to Minnesota after he made multiple false bomb threats, sent harassing text messages and made “swatting” phone calls to Marshall High School.

Zachary Morgenstern was subsequently sentenced to 41 months in prison.

“A hoax or a real threat is no different for us. We have to treat them the same because if it is real, we need to actually prevent it or to minimize the harm or damage that could be caused,” Rivers said.

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The FBI says people make hoax threats for a number of reasons, including to seek revenge or attention, to be in control or maybe as retaliation for bullying.

“Think before you post or before you make a threat,” Rivers said. “A hoax is not a joke and the ramifications are real.”

Individuals face a maximum of five years in federal prison for a hoax threat. State and local charges also can apply.

Call 911 if you learn of a potential threat or see suspicious activity.