Evergreen High School was locked down for roughly half an hour on Thursday morning after a 16-year-old boy made unspecified threats.

The Jefferson County Sheriff’s Office says the boy, who is a student at the school, is in custody. No weapons were found as part of the office’s response.

“School will resume normal operations as law enforcement completes their investigation,” JeffCo Public Schools said in a tweet.

The school remains on lockout, officials say.

Michelle Lyng, a district spokeswoman, declined to discuss the basis of the threat.

“Right now we are trying to assess the situation,” she said.

Wilmot Elementary School in the area was on lockout as the county sheriff’s office mitigated the threat.

Further information was not released.

Jesse Paul: 303-954-1733, jpaul@denverpost.com or @JesseAPaul