(CBS) – The unsettling story that people dressed as clowns intimidated some students at Waukegan’s Greenwood Elementary School is just that – a story.

Unit School District 60 officials on Wednesday said students admitted they “fabricated” the tale after seeing construction workers carrying tools at a nearby work site. That’s a far cry from the bizarre story they told authorities Tuesday, that three individuals in clown garb were looming outside the playground and made threats.

The school was locked down Tuesday as a precaution.

Officials say it’s part of a disturbing trend concerning the alleged sightings of “creepy clowns” across the country.  In some cases, these threats have been more about unnerving people.

“The national hysteria and social media proliferation surrounding ‘creepy/killer clowns’ has led to many parent and student concerns about safety in our schools, and around the community. We would like the community to know that we take all of these concerns seriously, and we work with police to follow up on all reported sightings and threats,” the district said in a news release.

Officials asked parents to urge their children not to get caught up in the clown hysteria or make stories up.

“Students coming to school with clown masks or weapons of any kind will not be tolerated. Additionally, any students perpetrating threats either online, or in person, will be subject to discipline in accordance with Board Policy,” the news release said.

The students who made up the clown story Tuesday will be disciplined, school officials said.

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