Prosecutors say Ryan Kang, 26, threatened Vernon Hills High School, Willow Creek Church and several people who live out of state.
They say the social media threats included school shootings, bombings and other violence.
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Investigators say Kang did not have the means to carry out any of the threatened attacks.
Kang was arrested on Saturday. He's been ordered held, pending trial on charges of falsely making a terrorist threat.
If convicted, Kang faces up to 15 years in prison.
"Social media and internet threats have become far too common," Vernon Hills Police Chief Patrick L. Kreis said. "These criminal acts disrupt our daily lives and promote fear in our communities. They will not be tolerated."