OGDEN — Students from Shadow Valley Elementary School were evacuated Tuesday due to a bomb threat.

The incident marked the second day in a row classes were canceled in a Utah school because of a bomb threat.

About 10:45 a.m., a letter outlining a threat was found in the boy's bathroom at Shadow Valley Elementary, said Ogden School District spokeswoman Donna Corby. The school was cleared about four hours later, with the assistance of bomb-sniffing dogs from Hill Air Force Base.

No explosive device was found.

The approximately 500 students of the school, 4911 S. 1500 East, were evacuated. Parents were contacted and told to pick their students up at an undisclosed "reunification location." Due to safety concerns, the location of the place to pick up students was not released publicly.

Ogden Police Lt. Danielle Croyle said parents were told where they could pick up their children. All parents were reminded to bring ID with them when picking up their children.

On Monday, Mountain View Elementary in Layton was evacuated and classes canceled after a pipe bomb was found on the school's roof.

"Maybe this is a copycat, but we're not taking that risk," Corby said Tuesday. "It's a great day if this just turns out to be a drill and we hope that's what it is."

She said students should expect to be back in school at the regular time on Wednesday.