"It was made to function," Horton said. "We have no suspects at this time, but we have a lot of video footage to go through from the [security] cams, at least a week's worth."
As they view the footage from 14 different cameras, detectives will be keeping a keen eye out for any footage showing someone throwing the pipe bomb onto the roof, or otherwise placing it there.
Meanwhile, classes resumed Tuesday as normal for 700 students and staff in the school, located at 2025 E. 3100 North.
Davis School District spokesman Chris Williams said Tuesday's return to classes went off without a hitch.
"The principal went on the intercom shortly after students had arrived to basically say, 'Glad you are here, it's a nice, sunny day,' and didn't discuss much of what had happened Monday," Williams said.
However, some students' parents made the day special for teachers and staff at Mountain View. "Parents were coming in with brownies for the teachers and hugs for the principal, showing their appreciation for now the school had looked out for their children," Williams added.
A 911 call from the school came in just after noon Monday, moments after the janitor spotted the pipe bomb on the roof. Horton said the employee originally took the device into the school, but by the time police arrived, the pipe bomb had been taken to the school's parking lot.
Students and staff were evacuated to a nearby church for the remainder of the day and parents were contacted by Davis School District officials to pick up their children there.
Layton police and firefighters, as well as the Davis County Sheriff's Office bomb squad responded to the scene. Two bomb-sniffing canine units from Hill Air Force Base also assisted, clearing the school's interior.
Horton said bomb squad technicians broke apart the pipe bomb using a special device that sprayed a high-pressure stream of water.
Anyone with information on this incident is urged to contact Layton police at 801-497-8300.