What makes a school threat credible enough to take seriously?

A fifth grader from Rush City, Minn. faces charges accusing him of writing a threatening message on a school wall. This comes the same week as Southwest High School in Minneapolis was closed for a day due to a bomb threat.

The question most people are wondering is: What makes a threat credible enough to take seriously?

In this day and age it seems it's a question school districts and law enforcement wrestle with far too often. At Southwest, no bomb or explosive device was ever found.

And now in Rush City, the arrested boy's parents are wondering whether what happened there required police intervention or not.

Chisago County Sheriff Rick Duncan insisted his office made the right call this week when deputies arrested an 11-year old 5th grader who attends Rush City's Jacobson Elementary School.

"We always side on protecting our schools," Duncan said. "Protecting our kids and our schools."

Days earlier, the boy had apparently left a threatening note scrawled on the wall of a timeout room inside the school. The sheriff wouldn't give specifics, but said the message included names of fellow students who were then crossed out.

"We went and talked to the parents and talked with the kid," Duncan said. "Then we felt, okay at this level, maybe we do have to take a kid in custody and go from there."

The juvenile arrest comes the same week that a "credible" bomb threat closed Southwest High School in Minneapolis. Luckily, no devices or explosives were found in the building.

National school security expert Ken Trump talked about the challenges district administrators and law enforcement face trying to differentiate a true threat from a possible hoax.

"What we're seeing is far too many school administrators are well intended, but they're responding emotionally rather than cognitively," Trump said.

Trump is based in Cleveland, where he is president of National School Safety and Security Services. His firm has examined similar cases all over the country.

Trump contends it's critical that schools answer several questions to evaluate a threat including:

1. What was the context of the threat and the motivation of the student who made it?
2. How was the threat delivered?
3. Can the person who made the threat actually carry out their threat?
4. Could they possibly have the tools, weapons, and know-how?

It's only when there's a high likelihood that a threat may become reality that schools should take the unusual step of evacuating or closing, like Southwest High School did Wednesday.

"There's a difference between a threat made in the heat of a fight where a kid says ‘I will kill you' versus one with a detailed plot found in a student's notebook or a website where there is evidence that the kid is gather resources and weapons to carry out that threat," Trump said.

As for the boy arrested in Rush City, his family tells Fox 9 that the child didn't even understand what the words he wrote actually meant, and that it should never have gone this far.

The 5th grader is now looking at a charge of disorderly conduct in juvenile court.