WASHINGTON, Feb 16 — Cathi O’Connor is credited with foiling her grandson’s alleged plot to shoot up a high school in Everett, Washington.

She called 911 after finding her grandson’s journal which, authorities say, detailed plans to carry out an attack at Aces High School.

18-year-old Joshua O’Connor appeared in court yesterday.

Police say this surveillance video shows the teen pointing a rifle at a convenience store clerk earlier in the week.

After she turned him in, detectives searched the grandmother’s home where they both lived.

In court, O’Connor’s attorney argued his journal entries were simply rants by an angry teenager.

Police say he wrote about building pressure cooker bombs, buying grenades and killing as many people as possible.

According to court documents, the grandmother found a rifle hidden in the teen’s guitar case in his bedroom.

Prosecutors say it’s the same kind of rifle Eric Harris used in the Columbine school shooting nearly 20 years ago. — Reuters