By Dan Wing

HADDONFIELD, N.J. (CBS) — In the wake of Friday’s tragic shooting at a Connecticut elementary school (see related story), parents across the nation were left with the same question:  could it happen here?

A local expert says it’s virtually impossible to know.

Dennis Tully, a retired New Jersey State Police officer who served as executive officer of special operations under the Homeland Security Bureau and who is now the president of Ronin Security Solutions, a South Jersey-based security consulting firm, says it’s hard to find any common thread or predict incidents like these.

“What we found through a lot of research and a lot of experience is, really, there’s only one constant among those involved at the heart of these incidents, and it’s always that, after the fact, they say, ‘We never thought it could happen here.’ ”

Tully says places like schools should hold training sessions for students and staff, instead of relying on security systems alone.

He also advises parents to look into schools security measures, and if they don’t have any in place, think about enrolling their children somewhere else.

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