A Powder Springs man is being held without bond for using social media to threaten students at McEachern High School, police say.

Daniel M. Gibbs, 19, is accused of posting a message on his Twitter account in which he threatened to "shoot up" the McEachern campus in west Cobb County, according to an arrest warrant.

The warrant stated that Gibbs threatened to get on top of the Business Technology building "and shoot all the [expletives] and shoot all kids with snap bags." The threatened attack was planned for last Thursday, the warrant stated.

A McEachern teacher saw the post and notified authorities.

Gibbs was arrested Thursday on charges of making terroristic threats, a felony. He is being held at the Cobb County jail.

James Arrowood, public safety director for Cobb County schools, told the AJC that Gibbs is a former McEachern student who graduated last year. He said he did not know of any incidents in Gibbs' background that might have prompted him to make such a threat.

"We don't know why he did it," Arrowood said. "It's just an extremely foolish thing to do."

Arrowood said security on the McEachern campus was increased until Gibbs was in custody.

Campus police  frequently monitor social media, Arrowood said.

"We randomly go on Twitter and Facebook to check for threats to schools or students," he said. "It's become an investigative tool for law enforcement."

He said young people "should be very cautious what they put out for public consumption." And he said it was the responsibility of parents "to make sure they know what's going on with their child's Facebook or Twitter account," saying Gibbs' actions "could affect his life forever."

Gibbs' family did not immediately return a call seeking comment.