Flagstaff High School was placed in a modified lockdown this morning after a report of a threat posted on social media. Marshall Elementary School was also placed in a shelter in place due to the incident. FUSD officials say police have arrested a suspect in the matter and classes returned to normal a short time later. FUSD is asking all parents to have a conversation with their kids about the expectations for social media use as it applies to student and school safety. These threats are never a joke and will be treated with severe consequences.