FAYETTEVILLE, N.C. — North Carolina school officials say they have upgraded the security of a social media network used by educators and students after a security breach led to an online threat against students.

A Louisiana 15-year-old is accused of posting the messages on Edmodo, which allows students to correspond with classmates and teachers but gives educators more control than other social media sites.

Cumberland County Schools Superintendent Frank Till said Monday passwords assigned to each student weren't secured, allowing the Louisiana teen to create fake accounts and start posting as if he was a member of Pine Forest High School's senior class.

The posts used the real names of several students and the most alarming post said he planned to "shoot up the school" on Monday and then kill himself.