POCATELLO (KTVB) -- A 15-year-old boy in eastern Idaho has been charged with threatening violence at a school and telephone harassment after a high school went on lockdown because of a violent threat posted online.

Pocatello police say the teenager - whose name hasn't been released - is in police custody.

Highland High School officials alerted police Wednesday of threats posted on Facebook and Twitter. A screenshot of the message exchange shows one person threatening to bring guns to school and "kill all the girls." According to the messages, the threats were made because the person was unable to get nude photos.

School resource officers restricted access in and out of the school on Wednesday to only the front doors.

However, officials say the high school would return to normal on Thursday.