File Photo – Lake Zurich High School | Photo: Google Street View

After two lockdowns Wednesday at Lake Zurich High School, police arrested a student for a social media post that indicated an act of violence was imminent, officials said.

Lake Zurich Community Unit School District 95 said in a statement the first lockdown, which was a soft lockdown, was issued after a shell casing was found at Lake Zurich High School.

The Lake Zurich Police Department was called to the school to assist school officials in the investigation.

During a soft lockdown, students remain in their assigned location and no visitors are allowed on or off campus.

School officials did not say where the casing was found. They urged parents not to go to the school during the lockdown.

Just over an hour after the initial statement was sent to parents, the school district said in an update they had lifted the soft lockdown.

No guns were located and school officials initially said no threat was identified.

However, a short time after the soft lockdown was lifted, a social media “immediate threat” was posted by a student.

The post “indicated an act of violence was imminent at the school,” district officials said.

The high school followed protocols, called 911 and placed the school on a hard lockdown.

May Whitney Elementary School, due to its proximity to the high school, also went into a hard lockdown for a short period of time.

One student was taken into custody by the Lake Zurich Police Department. No injuries were reported.

The police department swept the inside and outside of the building and authorized the lifting of the hard lockdown.

The school district did not say if the shell casing and the social media threat were directly related.

“Please know that many students and staff are understandably upset by today’s incidents. We will be developing a plan to provide support. More information will be provided soon,” the school district said in a statement.