MOUNT VERNON — The Jefferson County Sheriff’s Office and Secretary of State Bomb Squad are investigating a Saturday night bomb threat at the Continental Tire facility in Mt. Vernon.

Deputies responded around 8:42 p.m. Saturday to Continental Tire after receiving a report of a threatening note was found that read “third floor goes boom at 3 a.m.”

Internal security at Continental had already evacuated the Mixing Department before sheriff’s deputies arrived on the scene.

The Illinois Secretary of State Bomb Squad also responded. They searched the building but nothing was found.

Sheriff’s deputies cleared the scene at 12:12 a.m. Sunday. The bomb remains under investigation.

This was the third threat in a year received at the Mt. Vernon facility, with the Mixing Department being evacuated twice in June 2016 due to similar bomb threats. Neither threat was found to be credible.