MINNEAPOLIS (WCCO) — Investigators believe a teenager is responsible for an emailed bomb threat that led to the closure of several Twin Cities schools in May.

Lakeville police say the threat was received on May 20 by Lakeville South High School staff members, leading to the closure and search of all ISD194 schools the next day. Students stayed home and spent the day in online learning.

The threat was soon determined to be a hoax, and investigators called on the FBI’s Europe Division to help find the culprit’s IP address, which led them to a Lakeville-area residence. Dakota County Electronic Crimes Unit detectives seized devices from the home, and later determined a teen who lived there sent the email threat.

The Dakota County Attorney’s Office is working on charging the teen with making a threat of violence via an explosive device, and police say “a juvenile petition has been secured.”

WCCO typically avoids identifying suspects who have not been formally charged, and those who are minors.