Long Beach police detectives were at Poly High School Monday afternoon investigating a “vague” threat that was sent to a student, according to authorities.

Authorities didn’t reveal the content of the message but said it was AirDropped to a Poly student’s phone. AirDrop is a feature in Apple computers and phones that lets users wirelessly share photos, videos and other files with nearby devices.

Because the files can be sent without attaching a name or phone number, it’s sometimes been used to send harassing or threatening images.

In this case, detectives are still investigating but they have detained someone who may be connected to the message, LBPD Officer Ben Hearst said.

The school day continued as normal, according to Long Beach Unified School District spokesman Chris Eftychiou.

“We had a report of a potentially threatening message, but we have not had confirmation of credibility,” he said.