Police make arrests in Hellgate High School lockdown incident.

Hellgate High School in Missoula, Montana was placed on lockdown after a social media threat of an active shooter was reported just before 10:30 a.m. on Wednesday. The Missoula Police Department responded to the scene and began investigating while ensuring that students were safe. Law enforcement also searched a private residence but say a person of interest was not found there. Three girls have been detained as persons of interest in connection with the incident, and several others are being questioned. The lockdown has been lifted, and the school day is expected to continue as usual on Thursday.