Sonora Elementary School was placed on lockdown Thursday after a teacher reported hearing gunshots and seeing a person with a weapon dressed in camouflage.
After an extensive search of the area, police believe the report was unfounded.
Police Chief Mark Stinson said the teacher likely heard shots from a private firing range in the area, where sounds of gunshots had been reported earlier that day.
Police received the call from Sonora Elementary about 11:50 a.m. and searched the area behind the baseball field that had been pointed out by staff.
"We found no evidence of any human being on the other side of the fence," Stinson said.
As a precaution, the Greenley Road campus was placed on lockdown, meaning that students and teachers stayed inside locked buildings, for about an hour.
At the request of the Sonora Police Department, Sonora Union High School District also put Cassina High School, its alternative education campus on Barretta Street, on lockdown at 12:20 p.m. That lockdown also was lifted about 1 p.m.
Stinson said a search of the undeveloped land between the two schools by more than a dozen officers showed no signs of a person with a gun.
The scare began when longtime Sonora Elementary teacher and coach Karen Sinclair said a teacher contacted her about hearing shots and seeing a person dressed in camouflage with a rifle.
Sinclair radioed the school's main office, but before she could even finish her sentence, Principal Chris Boyles announced over the intercom that the school was going into lockdown.
Boyles didn't tell teachers about the reason for the lockdown. He said they simply followed their training.
Teachers participate in some kind of drill, such as a fire or lockdown drill, about once a month, Boyles said.
The lockdown occurred during the lunch period for second- and third-grade students, forcing teachers and staff to hurry them inside. They accomplished that within moments after the lockdown was called, according to Boyles.
The campus was eerily quiet as police scanned the area. Tuolumne County Sheriff's deputies and California Highway Patrol officers also responded.
Secretary Barbara Dresslar approached parents who arrived at the school and informed them of the lockdown.
"One of our procedures in our lockdown is for teachers to maintain a calm environment and composure," Boyles said. "The teachers did a great job of keeping the kids in a good place and making them realize it was safe as long as they were in lockdown."
About 30 fourth-grade students who were locked in the library crouched behind stacks of books and spoke in whispers.
Librarian Louise Steuben manned the front door and reassured students of their safety.
"They're scared … there's policemen on campus with guns," she said during the incident.
The lockdown was called off shortly before 1 p.m. Kindergarten finishes at Sonora Elementary at 12:20 p.m.
Boyles consulted with Stinson about allowing parents onto the campus to retrieve their kindergartners from the cafeteria while the lockdown was in effect, and Stinson advised that it was safe. Boyles said parents had to present identification before they entered the cafeteria.Once the back side of the campus was secured, staff members escorted some students to restrooms and allowed first-graders to eat in the cafeteria while it was still locked down.
The school's phone lines were tied up as parents called to ask about the situation. After about 1 p.m., the school returned to its normal schedule.
Sinclair congratulated Boyles, who is new to Sonora Elementary this year, on his quick response to the scare.
During the lockdown, police scoured the streets of Sonora for a suspect matching the description provided by the school.
A man wearing a camouflage jacket was arrested in downtown Sonora shortly before 1 p.m. Police said the arrest had no connection to the school incident, but the lockdown was lifted and police called off their search about the same time as the arrest.