(CBS Detroit) — The Macomb County Sheriff’s Office says deputies are making extra patrols to all schools after receiving reports of schools threats.

This comes after a 15-year-old at Oakland County’s Oxford High School killed four people — all students — and injured seven others on Nov. 30.

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Ethan Crumbley, who was a sophomore at the high school, has been charged with murder, terrorism, and other counts for the shooting.

In a statement issued on Thursday, Macomb County deputies say that in the last two days, they have received 28 calls regarding school threats, some related to the same incident already reported.

“School shootings are one of our biggest fears as a student, a parent, school staff, and law enforcement,” read the statement.

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“Please know that we are taking every report we receive with the highest priority. We have had deputies and investigators working these complaints throughout the night and are still investigating them currently,” the sheriff’s office added. “At this time, we would like to dispel any rumors by stating we do not and did not have anyone in custody for any of the threat complaints we’ve received.”

Anyone who would like to report a threat can contact Macomb County Sheriff’s Office non-emergency dispatch at 586-469-5502.

The jurisdiction includes Harrison, Lenox, Macomb and Washington townships, Mt. Clemens and New Haven. Threats made outside of the jurisdiction must be reported to the law enforcement agency patrolling that area.

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Read the full statement from the sheriff’s office below: