1 of 3 Around 20 vehicles from the DCSO and Douglas County School District, and a helicopter patrolled the surrounding area of Mammoth Heights Elementary School in hopes of locating Katherine Gould, 12, who was last seen leaving her home on Greenstone Circle -- just under a mile south of the school -- on her bicycle around 8:20 a.m. Tuesday. Dennis Huspeni The Denver Gazette Around 20 vehicles from the DCSO and Douglas County School District, and a helicopter patrolled the surrounding area of Mammoth Heights Elementary School in hopes of locating Katherine Gould, 12, who was last seen leaving her home on Greenstone Circle -- just under a mile south of the school -- on her bicycle around 8:20 a.m. Tuesday.