DES MOINES, Iowa (AP) -

Monitoring software on a school computer helped Iowa officials thwart a gun deal between three students.

Officials say a 15-year-old boy who attends East Union High School in Afton was arrested Jan. 9 on weapons and other charges. He'd been communicating about a gun deal via school computer with students at Johnston High School and Lincoln High School in the Des Moines area.

The Johnston district school computers have software that alerts officials to certain words such as "gun."

Afton Police Chief John Coulter says the software alerted the software company, which notified Johnston school officials, who notified East Union High School.

Police haven't found the gun yet.