GREGORY, S.D. - After a series of school lockdowns in the area, the Gregory Police Department is urging parents to talk to their children about the dangers of sharing threatening Snapchat images. In a Facebook post, the department confirmed that these images were the cause of the Gregory school lockdown and closure earlier this week.

“Many of these images were the same images seen last week in Winner, and again yesterday in Boyd County NE during their lockdown,” the department wrote on Facebook.

Authorities are actively investigating the source of the images and pursuing potential criminal charges. Several pieces of evidence have been seized and handed over to the Division of Criminal Investigation for further analysis.

“Thus far throughout the course of the interviews and investigation, there has been no information to suggest our school was in any danger aside from the images being sent around by students through Snapchat,” the police department wrote.

Gregory Police are encouraging anyone with information or concerns about suspicious images to contact law enforcement.

According to the FBI, making a threat—whether over social media, via text message, or through email—is a federal crime. Individuals who issue such threats can face up to five years in federal prison, in addition to potential state or local charges.