WATCH: Police say teen with loaded gun threatened to shoot up NYC high school

A student was arrested after allegedly posting a threat online and being found with a gun in their backpack at a New York City high school on Thursday, officials said.

​A student was arrested after allegedly posting a threat online and being found with a gun in their backpack at a New York City high school on Thursday, officials said.   A student was arrested after allegedly posting a threat online and being found with a gun in their backpack at a New York City high school on Thursday, officials said.