The speaker, from the Pennsylvania Attorney General's office, warned of serial killers, sex offenders and Al-Qaida in Lower Merion, Montgomery County.
It was part of the "Operation Safe Surf" program, which travels to schools across Pennsylvania to educate kids on internet safety.
But, according to the Lower Merion School District, the presenter during Wednesday's assembly to fourth and fifth graders at Merion Elementary School put quite a scare into some kids.
"A couple of teachers had some concerns over the way the message was being delivered and if it was age appropriate," said Doug Young, Lower Merion's director of community relations.
The presenter told kids their homework assignment was to look up sex offenders in their neighborhood on the state's Megan's law website.
Then, while explaining how to use cell phones for emergencies, the presenter's joke about being kidnapped by Al-Qaida fell flat.
He also warned a serial killer could be at the other end of the online video games kids play.
Joe Peters, a spokesman for the Attorney General's office, said "the glitch was in the delivery" and "no malice was intended here. The agent was trying to get the students' attention. These programs are dynamic and interactive."
"We apologize and understand why a few were offended," Peters said.
According to the district the agent tweaked his delivery for the second group of kids that afternoon.
Some parents said a heads-up about programs like this could help.
"I think some parents would prefer to talk about that with their kids or get a heads up to prepare them," said Lauren Krivitzky.
The employee involved is getting counseled on his delivery, but he is not being punished.