SIOUX CITY, Iowa: Authorities in northwest Iowa say they have placed three schools on lockdown as they search for a male student who they believe brought a gun to school earlier in the week and made threats.

The Woodbury County Sheriff’s Office says Lawton-Bronson Community School, Siouxland Community Christian School and Woodbury Central Community School were locked down Wednesday as a precaution. Law enforcement personnel are at all three schools.

Sheriff Dave Drew says authorities believe the Siouxland Community Christian School brought a gun to school earlier in the week and made threats. He did not elaborate, but authorities are now trying to find the student.

Drew says the two other schools are on lockdown because the student has ties to them.