LAFAYETTE -- Police detained a person for questioning Friday afternoon, hours after students at Acalanes High School were ordered to remain in their classroom because of a potential threat, authorities said.
The lockdown went into effect Friday morning, when a threat posted on social media came to the school's attention, Contra Costa Sheriff's Office spokesman Jimmy Lee said. Police declared the area safe after searching the campus and lifted the lockdown around 12:30 p.m.
Police sent out an alert at 12:33 p.m. that one person had been detained off campus, and that officers were still investigating. The nature of the threat was not revealed. The person was not on or near the campus when officers made contact, police said.
At least one student at the school sent a message on Twitter about an expletive that was written, directed at police and the school, inside one of the girls' bathrooms.
Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rderh