Four schools in Antioch were briefly locked down Thursday morning after someone reported hearing what sounded like gunfire near Deer Valley High School.
Antioch police Lt. Leonard Orman said a groundskeeper saw a male walking near a baseball field behind the high school shortly before 8:30 a.m. and then heard a popping sound that he thought could have been a gunshot.
Immediately after the sound was heard, the male took off running, Orman said.
The groundskeeper reported the incident to police and the school district, and Deer Valley High School, Dozier-Libbey Medical High School, Diablo Vista Elementary School and Lone Tree Elementary School were placed on lockdown while police investigated the report.
Police did not find any shell casings at the scene or any other evidence that a gun was fired, Orman said.
The lockdown was lifted at about 9 a.m.
All Antioch Unified School District students and staff are safe and classes have resumed at the schools, according to the district.