Why Did LA See a Legit Bomb Threat Where NYC Saw a Hoax?

Context is key when it comes to deciding whether a bomb threat like the one that shut down the Los Angeles school system is real — or a hoax.

So said security experts interviewed by NBC News just hours after the feds concluded the threat that shuttered the nation's second largest school system on Tuesday — but which New York City officials ignored — was bogus.

"Each threat must be evaluated individually and this means that the context and nuance of how the threats were perceived in New York and Los Angeles came into play," Chris Dorn of Safe Havens International, a non-profit that specializes in helping school systems with security issues, said in an email.

Los Angeles is only about an hour's drive from San Bernardino, where earlier this month a married couple who'd become radicalized murdered 14 people and wounded 21 more.

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"It is not uncommon (nor is it a bad idea) for schools in an area near a recent attack to be extra cautious," Dorn wrote. "We saw schools in Connecticut that would go on a lockdown for the slightest possibility of danger because of their proximity to Sandy Hook and the heightened sense of awareness. We always have to work to control this fear but still allow past incidents to inform us."

Anthony Roman, a top investigations and risk management analyst, agreed.

A sign at Hamilton High School reading "School Closed" in Los Angeles, Dec. 15, 2015.
Jonathan Alcorn | Reuters
A sign at Hamilton High School reading "School Closed" in Los Angeles, Dec. 15, 2015.

"The LA region suffered a major attack, so they will be a tad more sensitive," he said. "They can never be blamed for erring on the side of caution."

Still, in closing down the LA schools officials there handed whoever made the threat a victory.

"You create a social impact when you close schools," Roman said. "All those parents who have to leave work, all those kids who were scared."

"Body counts is not the only intention of terror, it's disrupting and changing our lives. That's why this threat of attack was partially successful."

As for why New York City Police Commissioner Bill Bratton was so quick to dismiss the bomb threat, Roman said the NYPD has "a very robust mixed intelligence unit" that has been extra vigilant since the 9/11 attacks and they have the resources in-house to quickly vet any potential threats.

"By comparison, the LAPD is a third the size and has a third the resources," said Roman.

Large governmental agencies like the Los Angeles Unified School District deal with threats all the time, the experts said.

"The large percentage of threats are generally not the tool of an attacker but of a prankster or disgruntled student or employee," Dorn wrote.

Still, each one has to be taken seriously.

"There are a variety of tools used by schools and law enforcement ranging from checklists to gather information about the threat to in-depth review of the available facts done at the top level of the organization," Dorn wrote.

Roman said law enforcement looks for a "figurative fingerprint" and check to see whether the "syntax matches the content" in a threat.

"They ask, 'What's the source?" he said. "They ask questions like, 'Is it really coming from overseas, or is it masked to look like that?' There are tell-tale signs."