An Instagram user posted an image with a rifle and the caption "gonna shoot up the school at 11:00 am," the outlet wrote citing police.
As of 11 a.m., students were being allowed to move around the building but not to leave or re-enter, the report said.
Only hours before the school locked down, Philadelphia School District announced that it received a $1 million to combat violence at Bartram High, according to WHYY.
Click here for the full report from CBS News.
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