DUNCAN, S.C. (AP) – Authorities say the person who made online threats to kill Jewish and Muslim students at a South Carolina high school lives outside the United States.

Spartanburg County sheriff’s Lt. Kevin Bobo said in a news release that because of this, the investigation into the threats against Byrnes High School has been turned over to the FBI’s terrorism task force.

Bobo says the threats don’t appear credible.

Spartanburg School District 5 said the online poster threatened to attack Byrnes High on Tuesday and posted pictures of a person in a gas mask and a knife with a swastika on the handle.

Deputies increased patrols near and at the school; no incidents were reported.

Byrnes High has about 2,300 students and is one of the largest high schools in South Carolina.