NOVATO, Calif. - A guest speaker who brought in a grenade for a history class at Novato High School prompted a shelter-in-place for the school, according to the Novato Police Department.

When the grenade was discovered at about 12:10 p.m., the airport called Harbor Police officers and K-9 units to investage. San Diego Fire-Rescue’s Metro-Arson Strike Team was also called in and ...