ROGERSVILLE, Tenn. (AP) — Police say two Hawkins County teenagers made plans last year to shoot up a high school and were studying the 1999 Columbine shooting.

The Kingsport Times-News reports (http://bit.ly/1ufv8rw) Hawkins County Sheriff Ronnie Lawson said authorities became aware of the plans last October after they were alerted by a counsellor for one of the boys.

The boys, ages 16 and 17, were charged with conspiracy to commit first-degree murder on Thursday. Both already were in state custody on other charges.

Deputies searched the home of the younger boy last December, seizing guns owned by the boy's father as well as journals detailing plans for an attack, floor plans of the high school, fire crackers and gun powder.

Deputies also found Internet videos of the boys with AR-15s and Molotov cocktails.